Well, my sentinel M16 clone from fasttech has been with me for about 6 months and I thought I'd share some thoughts. It's had quite a hard life and has seen a lot of use on a daily basis with multiple atty changes each day It's worked faultlessly. I mean totally faultlessly. Not a single misfire. Every 510 atty that I've shown it has fitted perfectly. Totally flush mounted. The top cap, 510 and floating centre pin are in good order and the threading on the main body parts is silky smooth (it was never bad but it's certainly got smoother with age) The button press is still as firm and positive as day one and it's easy to adjust the throw. Maintenance? Once a week I strip it down and give it a clean in hot soapy water followed by a quick rub with some brasso. I eventually got round to doing a proper polishing job with wet and dry a few weeks ago and it now looks better than the day it arrived. Possibly the best 11quid I ever spent.