Band-It JS2539 - 1/4" wide by about .020" thick. There's a tool for installing them, but you can do it reasonably well with some duck-billed pliers for these small versions. Pull them tight and then bend them back over the opposite direction and squeeze. Hydraulic hose shops should have these. I've seen red high-temp RTV applied to the ends of the sleeves to keep them from unravelling.