I read a while back about installing a grease fitting in place of the abs sensor to grease the hub/wheel bearing.

I found these Riffraff Diesel: Front ABS Grease-able Block Off Fitting from clay while looking at the cost of an AE " they were on the same page ".

My question is this ......

By installing and using them which Bearing dose it apply grease to ? The needle bearing that the front axel shaft rides on. Or the actual sealed wheel/hub bearing.

Any one using these ? how are they ? do they really help the longevity of the front wheel bearings. Ive put 2 or 3 sets of hub assy on my truck in 6 years and if it will help not having to do that "As much" I'm sold.