The only straps I'll ever buy again...Kevlar. These are thin enough to go in the slots in your frames, but strong enough to take the abuse without shredding like the cheap freebie straps.
I personally have gone through hundreds of straps trying to find perfection. I tried kevlar with rubber in them, and they we're too thick for most frames, and also the rubber cracked and tore up in a couple of months. I got a pair of these Kevlar straps from OAS Hobby over 2 years ago, and I still fly with them on my quad every day. That's what inspired me to have these created, by the same manufacturer in China. It was kind of ridiculously expensive spinning up a factory for a few hundred straps, but I knew that these were exactly what I wanted to have for you.
The straps are 250mm long and have a solid steel buckle.