Reflective ankle bands are required on many after-dark rides, and they're a good idea even if they aren't required. These are 2" wide to hold your pants leg securely out of your drivetrain.

They're made of a very high quality reflective material that's soft and comfortable and also remains just as reflective when it's wet. The velcro holding them on is 1" wide, which means that there is still substantial reflective surface visible all the way around, not completely blocked where the velcro attaches. 
The rougher "hook" side is a shorter piece so that it won't snag your socks.

Sold in pairs.