The Easy-Fit Fencefast Concrete-In post holder is ideal for use when the ground conditions that you are inserting the post into required the additional use of concrete to make it secure. The base of the holder itself sets into the concrete and then clamps secure the post into place. They can be used with all styles of fence panel but are compatible with post sizes between 90mm - 105mm.For post sizes 85mm - 105mmFor setting into concreteBase sets into concreteClamps secure fence post