Mag tube extension arrived this morning. Delivery was super quick, ordered late Thursday and it shipped Friday afternoon. The description said "new" but were taken off 870 Police models that were being modded by another company. Whatever...they were 20 bucks cheaper than anything else I found and were local-ish anyway. I don't know if any of you have been looking online much lately but there isn't much available for sale right now for all things "shotgun". Everything is sold out or out of stock. Especially for security or short barrelled models. Installation was very straightforward. Removed the barrel for just ease of working. Stuffed a shop towel down the open tube and used a rotary tool grinding bit to remove the tube dimples that will allow the follower more travel. Pulled the rag, gave the tube a quick vacuum and then wiped and lightly oiled the follower, tube threads and the newly exposed metal inside the tube. Re-installed the barrel. Inserted the new, longer tube spring and screwed on the extension. Slid the tube clamp with sling swivel into place, tightened the screw and a few wipes all around with gun oil...done. Tested with loading and unloading...all good, super slick. Next will be to get some shooting in and see how the extension holds under recoil. I read a number of reviews on single and two-piece extensions...first off this particular extension is an OEM single piece, but I was impressed with the reviews that favored the 2-piece extension. The 2-piece being apparently better at holding the barrel guide ring in place by using a threaded collar and the extension then threads into the collar. I don't know, we will see. I've always been hesitant to use a tool on the end cap and now on the extension. I've never gone more than hand tight. I've used vice grips and a rag once to remove the end cap after the gun sat for a few days after a damp outing. Anyone ever use tools to tighten the end cap?