I needed 4 16.5 strips to line both sides of the driveway and some small loops. One would not light at all but was returned in exchange and the other 4 (including new from exchange) work great. It's VERY lovely and bright. My driveway looks like a runway.Installation was tricky since we have a concrete block, maybe six inches high, lining the driveway. The clamps were too weak and quickly broke. We got more heavy-duty, and Jerry rigged a few things, and it works great.The only issue is that the photocell we used on the prior old system turns on these lights earlier, in the late afternoon, since it is mounted inside the carport, which is more shaded. I may have to add a resister or replace the Photocell, and the same setup didn't turn on too early. It shouldn't be different since the photocell is the same and in the same place. I am not sure if the load (different resistance) from the string is different; that should not make a difference. It is beautiful once on and in place; love the bright, continuous blue light.