These Single Stack Magazine Pouches are designed to be a secure universal fit for almost any 7-8rd single stack .45 cal magazines. The extended option will increase the height of the pouch  to accomindate extended base plates and the additional length associated with 10rd .45 cal magazines.
 
Magazine Sizing Chart
Size 1
Fits Most Single Stacked .45 Cal Magazines. (see chart for manufacturer tested compatibility) 
Colt/Para 7 Round .45 Cal.
Colt/Para 9 Round .45 Cal. (Size 1 Extended)
 
Size 2
Fits Most Metal Double Stacked 9mm/40 Cal. Magazines. (see chart for manufacturer tested compatibility
S&W 17 ROUND 9MM 
S&W 15 ROUND 9MM 
S&W 21 ROUND 9MM (Size 2 Extended)
S&W 15 ROUND .40 CAL 
S&W 10 ROUND .40 CAL 
SIG 17 ROUND 9MM 
SIG 15 ROUND 9MM
SIG 21 ROUND 9MM
SIG 20 ROUND 9MM 
FNH 17 ROUND 9MM
FNH 21 ROUND 9MM (Size 2 Extended)
H&K 17 ROUND 9MM
H&K 15 ROUND 9MM
H&K 20 ROUND 9MM (Size 2 Extended)
CZ 17 ROUND 9MM 
CZ 15 ROUND 9MM
 
Size 3
Fits Most Polymer Double Stacked 9mm/40 Cal. Magazines. (see chart for manufacturer tested compatibility) 
Glock 17 ROUND 9MM
Glock 17 RD 9MM W/ +5 RD Base Plate * (Size 3 Extended)
Glock 15 ROUND 9MM
Glock 15 RD 9MM W/ +5 RD Base Plate * (Size 3 Extended)
Glock 15 ROUND .40 CAL
Glock 13 ROUND .40 CAL

Size 4
Size 4: Fits Most Double Stacked .45 Cal. Magazines. (see chart for manufacturer tested compatibility) 
Glock 13 ROUND .45 CAL
 
Product Specific
"P/S" Marked magazines denote a Product Specific pouch. (these pouches are made specifically for that magazine)
Staccato 17 ROUND 9MM 
Staccato 21 ROUND 9MM