I own one of these but the tiny button fell out last night while I was walking home so I'll never find it. I'm currently using my garage roller door key to change light intensity lol.
This item used to appear on Ozbargain for a couple of $ at stores like LightInTheBox and Gearbest, but for ~$10 I prefer the garage key. I haven't seen it listed cheap for a long time. Does anyone have a source?