precisionworks
Flashaholic
Concealco uses leather straps with a 'one-way snap'. These snaps have been used for years on high end police/military gear. They don't come loose by accident - in fact, they are not easy to unsnap when you want to do this. But it does provide positive retention.but I have been wary of clip on items ever since.
Very well made & a bargain for about $20 each.
http://www.concealco.com/miva/merchant.mvc?Screen=CTGY&Store_Code=ACL&Category_Code=053SFH