As you can see I have a adjustable pipe section installed and I'm wondering do you secure the sleeve that slides up and down with some short self-tapping screws into those small slots...or do you leave it as is...??? This pipe section worked out well for me...it lets you turn your stove into position when the pipe is all installed...since the adjustable sleeve turns or spins freely. Anyways I finally have it all installed..took me a couple of days..had to chip out my chimney for the thimble and get some special drills and hardware...I will fire up the Thelin tomorrow..or maybe tonite...I'm letting the silicone dry and set-up..I'm buring MWP..Maine Wood Pellets...the pellet plant is about 2 hours from here..got 3 ton for $220.00 a ton...down the road in Medway Maine...hope I have enough...this being my first pellet stove..NO MORE WOOD...my body take take it!