Reaper posted several photos of his Tri-Rail Mount on Remington 870 on Remington 870 Forum:

Shotgun Tri-Rail Mount

Shotgun Tri-Rail Mount

Shotgun Tri-Rail Mount

Shotgun Tri-Rail Mount

Recommended Products:
Tri-Rail Shotgun Mount

Tri-Rail Shotgun Mount

Tri-Rail Shotgun Mount
Tri-Rail Shotgun Mount

Tri-Rail Shotgun Mount

Tri-Rail Shotgun Mount