ATI Outdoors Shotforce Top Folding Shotgun Stock Urban Combat. The manufacturer says that ATI Outdoors Shotforce Top Folding Shotgun Stock is compatible with Remington Model 870 Winchester Model 1300 Mossberg Model 500 Mossberg Model 835 Winchester Model 1200 Mossberg Model 590 Mossberg Maverick 88 12 Gauge Mossberg Maverick 88 20 Gauge Mossberg Model 535ATI Outdoors A.1.50.1155: Shotforce Top Folding Shotgun Stock Urban Combat