Since the sigma is a knock off of Glock, a glock 17 holster will work with the sigma. Tried it personally with my crossbreed holster for my g17 and my buddies Sigma. Hope this helps
GOFFA Council Member
Gun Owners For a Free America
"Today, we need a nation of Minutemen, citizens who are not only prepared to take arms, but citizens who regard the preservation of freedom as the basic purpose of their daily life and who are willing to consciously work and sacrifice for that freedom."
~John F. Kennedy