Having ordered and purchased a case of 12 sets of strings of white 'Y' incandescent white lights, all arrived quickly but wiring of two strands were loose enough that all bulbs had to be re-inserted firmly before proper functioning and even then, lights kept blinking while installing. Once securely fixed in place, all 12 strands worked well. For the >***$ CDN price tag, 30 minutes of extra effort paid off. 'Y' shape means that the plug is in the middle of the strand, with nothing on one end and the socket is on the other end; design makes creative arrangement easy. Built-in fuse in plug head is an added safety feature. Bulbs are standard North American incandescent mini-lights, white light with green plastic (for green plastic-covered wires). Note to purchasers of this product: test all strands as soon as they arrive, otherwise you run the risk of running out of time to return merchandise for reimbursement (minus shipping and handling and taxes). I rate this product 10.5 out of 12, or 87.5% "Very Satisfactory".