ANH Holster, although we see Stunt holsters on most Stormtroopers, strap size and color varies from trooper to trooper as well as position on belt.
Majority having long straps
Approximate guide
Hero Holsters, the following are what are seen on Han and Luke, E-11 style with the 4 rivet attachment, although slightly different
Approximate guide
A nice shot of Han and Luke both with E-11's holstered and Han c