Knee Savers® are a catchers best friend.  They are pads that go on the bottom of the shin guards.  They strap on to the straps you have on the back of the shin guards.  They help your knees from getting beat up because when you are catching you squat all of the time.  I catch a lot.  If you catch for more than 3 innings you start to get sore.  It is not fun.  Knee Savers® are mainly used by kids because they can slow you down when you are trying to throw out the guy at second or 3rd or were ever.  They are very comfortable.  I only use them if I am tired.