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STREN-FLEX® Synthetic Slings





Our wide variety of web slings are second to none. Made from the highest quality materials, right here in the USA, you'll be hard pressed to not find an exceptional sling for your needs. Learn more below, or contact us to find out how you can purchase these world class slings.

Equipped with soft color coded covers, our roundsling's capacities are easy to identify while they protect your load. Their architecture also allows for no stitched edges to damage your product, while also be easily adapted to hold uneven shaped loads. Contact us if you have any questions!

Our custom designed boat slings are made from low stretch polyester webbing. We build in cordura edge guard for extra protection, and come with any options you could need to safely lift your boat. Talk with us today to find out how we can help supply your boat lifting needs.


Synthetic Sling Materials

Synthetic slings are made of nylon and polyester to suit various applications. When choosing a material, Stren-Flex® recommends considering a material’s resistance to specific chemicals, temperature, and stretch factor. Stren-Flex® recommends nylon web slings for most web sling applications, and polyester roundslings are useful in applications requiring low stretch and acid resistant materials. All standard Stren-Flex® slings are sewn using nylon webbing unless polyester webbing is specified by the customer.




Nylon is the most widely used general purpose synthetic web sling. Nylon is unaffected by grease and oil, and the material has excellent chemical resistance to aldehydes, ethers, and strong alkalies. However, nylon slings are not suitable for use with acids and bleaching agent or at temperatures in excess of 194° F (90° C). The stretch of a nylon sling at rated capacity is approximately 8-10%. Gorilla Edge™ nylon slings contain energy absorbing fibers in the edge of the sling webbing that that improve cut resistance and web protection. Gorilla Edge™ slings provide the increased abrasion resistance needed for many industrial applications. Gorilla Edge™ has proven its durability, and is considered the best product in it's class. Polyester web slings are used primarily in conditions where acid is present or a minimum stretch is desired. Polyester is unaffected by common acids and hot bleaching agents, but the material is unsuitable for use in conditions where concentrated sulfuric acid and alkaline is present. Polyester is also unsuitable in locations where temperatures exceed 194° F (90° C). Stretch of a polyester web sling at rated capacity is approximately 3%. Also see Polyester Roundslings.


What's the Best Material for the Job?

Sling Types

Synthetic web slings come in a variety of different types in order to better serve a particular purpose. Multiple sling configurations allow a user to find a sling that is most adaptable to the application for which the sling is used. Stren-Flex® follows a standard numbering system and terminology, and our representatives can help you find the right sling configurations to fit your needs.





Type 1 is a versatile sling type that has steel end fittings to allow the sling to be easily used in basket or choker configuration. These fittings also reduce wear and allow easier connection to most hoist hooks. Basket capacities from 4,800 to 67,000 pounds. Web widths are from 2-12 inches. Type 2 slings are the same as Type 1 except each end has the identical triangle. This sling is used only on vertical and basket configurations. Basket rated capacities are identical to Type 1. Type 3, also known as eye & eye flat slings, are very popular slings which are stocked in multiple capacities. eye & eye slings are very adaptable and are a good choice in many lifting situations. The flat eye is usually easier to remove or insert into limited spaces. Basket capacities from 2,400 to 132,000 pounds and web widths from 1-12 inches are available.




Type 4 eye & eye twist slings are identical to the type 3 slings except the eye of a type 4 is twisted to stand open. Eye and eye twist slings are recommended if the sling is to be used in a choker hitch. Basket capacities and web widths correspond with Type 3. Type 5 endless slings are versatile and used for general purposes. The slings can be rigged in an unlimited amount of ways, and they can be readily adjusted to compensate for wear. Endless slings are popular and easy to use. Basket capacities from 4,800 to 107,400 pounds and web widths from 1 to 12 inches are available. Type 6 reverse eye slings are heavy duty slings that have an eye and body covered with wear pads. Eyes stand open at 90° to the sling body allowing easy choker or basket hitches. Stren-Flex® manufactures Type 6 slings with basket capacities ranging from 7,200 to 70,000 pounds and web widths which vary from 2 through 6 inches.



Type 8 slings are used in basket hitches where a wide heavy duty sling is required for load stability and for proper handling of fragile or finished surfaces. Type 8 slings are for basket hitch only with capacities ranging from 19,200 to 108,000 pounds available in web widths from 6 to 24 inches. Type 9 cargo slings are used in basket hitches to provide a large surface area for load stability and protection for finished or fragile surfaces. The eyes of a cargo basket sling are small and can easily accommodate small hoist hooks.


Load Factors

After identifying the material type, the next consideration must be the rated lifting capacity required. Remember that the rated lifting capacity of the sling must often be greater than the weight of the load to be lifted. Because the angle of pull on the leg of a sling varies with the leg angle, forces may be exerted on a sling greater than the user may expect.

To calculate the load on a particular sling leg proceed as follows or use our load calculator:

  1. Take the total weight of the load and divide this by the number of legs supporting the load. For example, assume a 2,000 pound load is to be supported by 2 legs of a sling. The above will give a total minimum weight on each leg of the sling of 2,000 pounds divided by 2 legs or 1,000 pounds.

  2. Determine the load factor by observing the load factor chart. Ex. Assume that the leg angle will be 60°. The load factor for 60° from the load factor chart is 1.154.

  3. Multiply the load factor times the minimum weight to be supported by the leg, i.e. 1000 pounds times 1.154=1154 pounds. The rated sling capacity needed is then 2308 (1154x2) pounds in basket capacity to safely lift the 2000 pound load.


Ordering Synthetic Web Slings




When ordering a synthetic web sling from Stren-Flex® follow the basic guidelines that follow. Identifying sling type, number of body plies, grade of webbing, web width, pull-to-pull sling width, and sling material is essential in order to receive the correct sling that is required. The sample part number below is a proper example of an eye & eye type sling with two body plys, heavy duty web, 2 in. web width, 3 ft. long sling from pull-to-pull, and type 4 twisted eye made of nylon material.

  1. Number of Body Plys (1-4)

  2. Grade of Webbing
    - 9 (9,800 psi - Heavy Duty)
    - 7 (7,000 psi - Light Duty)

  3. Width of Webbing

  4. Sling Length
    - Measure Pull to Pull

  5. Sling Material
    - Nylon or Polyester
    - Regular or Monster Edge

CAUTION: These tips are provided as a starting point in the selection process and are not universally applicable. Please consult our experts for the solution to your specific application problem.