ROK Straps are superior bungie cords. They are designed to be safe and long lasting during prolonged outdoor use. Each end of the strap consists of a sewn loop, allowing it to be securely fastened to a wide variety of frameworks without concern for scratching or marring the surface, or for a hook coming released under tension and finding its way into an eyeball. Cargo secured by the ROK Strap is easily accessed via the side-release buckle. Most of the ROK Strap is simple webbing, adjustable thanks to the buckle. One side of the ROK Strap has a short segment of a durable natural rubber, giving the strap some elasticity, but not enough that unintended recoil will likely result in the strap finding its way into an eyeball. The rubber is contained in a polyester braid for UV protection and additional durability.
For securing cargo to a bike rack, my preferred model is the Pack Strap. These expand from 12” to 42” inches. They are 5/8” wide and are rated to carry up to 55 lbs. I find this is the right size for most cargo and have used it to transport: sleeping pads, folding chairs, toilet paper restocks, a year’s supply of paper towels, pizza, and takeout yakisoba.
The smallest model is the Commuter Strap. These expand from 12” up to 28”. They are 1/2” wide and are rated to carry up to 40 lbs. If you just want to lash down a jacket or sleeping bag, these may be appropriate. They are long enough to secure common small cargo on a bike, but I would always rather have the extra range of the Pack Strap for handling awkward loads.
ROK Straps are also available in the ATV Strap model. These expand from 18” to 60”. They are 1” wide and are rated to carry up to 100 lbs. Apparently these are popular among people who ride motor-scooters. The 18” minimum length is too large for some of what I want to attach to a bike, and I’m not keen to carry cargo that would require the 60” maximum length. I saw a photo once of somebody who used these to attach a 45 gallon trash can to the back of his scooter. If that’s what you need to do, I guess consider these, but for what I find myself carrying I don’t need the extra length or weight rating of these over the 42” Pack Strap. This model stays at home in my bag of miscellaneous bondage.
The above measurements are of the ROK Straps when the rubber is at rest. When under load, all three models can stretch about an additional 4”.