The straps talked about above are solid, one piece belts that run all the way around and through the channel on the back of the sporran. They typically range between 1/2" and 1" in width.

I use a strap that has trigger snaps on each end and an adjustable buckle on the back that attaches to the D-rings on the back of the sporran, or the D-ring strip that slips through the channel of the sporran.

I prefer the trigger snaps because they allow for quick and easy on/off of the sporran and once it's sized to fit, I don't have to monkey with a buckle again. I can still swing the sporran to the side for restroom visits or sitting or slow dancing and the trigger snaps swivel and flex more than a one piece strap so less pressure is applied to the groin.