Cuttable every 3 LED lights 18 LED lights on 11.8 inch if the led strip is too long, just cut it every 3 LEDs at the designated cut marks USB powered you can plug the USB switch to the USB power adaptor OR powered from any USB device how is computer, desktop, laptop, tablet, powerbank etc. dimming switch adjust brightness as you want 5V working voltage low cost & energy efficent Package content: 1)1pcs* 11.8 inch LED strip with button dimmer 2)2) 1pcs* 5V/1A USB adaptor