This is compatible with MOLLE interface tactical gear (i.e. vests, leg platforms, battle belt, etc.)  This pouch also has plastic reinforced side walls.
Back webbing side is 3x6" (7.6x15cm)

MOD Large Multi-Use Pouch Can Hold:
3x 20 Round DMAG
3x 14 Round DMAG
3x 20 Round HELIX
4x M4/M16 magazines
4x T15 Magazine
4x TMC Magazine
4x Stormer Magazine
3x CF20 EMF100 Magazine
3x DYE DAM Magazizne
3x Milsig Magazine
3x M17 Magazine
3x MaxTac Magazin
M249 Magazine  005142