I just got through installing two Vang Comp Big Head Safeties in my two 870's. One 870 is in my hunting gun, the safety should be great in the goose pit when wearing gloves. The other went in my home defense gun. Installation is extremely easy. Each took less than 15 minutes to install from start to finish.
Here is the safety in the HD gun.
Here is a picture of the Vang Comp Safety.
There were some small differences between my older HD gun and the newer hunting gun with key safety. The older gun had only a spring and ball bearing(sp?). The newer gun had a piston looking thing in place of the ball bearing. The piston looking device makes the safety feel much smoother. I may buy one for my older gun.
Here is the safety installed in the newer trigger group.
Overall I am very happy with the Vang Comp safety. For $10 on the Brownells website you cant go wrong!