Hudson Supplies offers the Fastmag Gen III family of magazine carriers and recently came up with a flap add-on at the request of customers in Canada for additional retention and protection of magazines from the elements.
Made from laser cut laminate it is simple to mount to the Fastmag.
Hudson Supplies products can be procured by agencies, departments, and units in Canada from Rampart International.
Flap management kinda negates one of the perks of the FastMag, but if there is demand, this looks like a well-done pretty fancy addon.
Might be worth adding some loop to the inner flap so can fold down / prep open top access.