Review on Set Of 20 Retrofit Recessed Downlight Housing C Clips With Self-Tapping Screws - Compatible With Torsion Spring For Easy Hook-On Feature Ideal For Down Light Can Lighting (10 Pairs) by Sanny Hoffman

Works perfectly for can lighting. Included self tapping screws a plus! Although 1 bag did not have it. Good thing I had exactly the same sizes in my tool box. Ofcourse with self tapping screws it's a pain making a mark or a dent at the beginning specially when you're in an 8 foot ladder and looking up. It's hard to put pressure on it without the screw coming off the bit a few times. It took me about 5-7 minutes for a screw to penetrate the can (rest included - not that young anymore). I don't know but I'm thinking either the screw is just dull or that can is made out of steel! I see 2 layers in the can though so that could be it. Just keep at it and stay patient. I also had to buy the Dewalt DWARA100 Right Angle Attachment for my driver which made things a lot easier. One thing that may be easier is you can also install it with the screw hole bottom side.