3M provided me with a free sample, and I love this hook!!  I am getting ready to purchase a few more!    I have glass French doors at the main entry to my home and have struggled with finding the right thing to hang wreaths on those doors.  It's been a challenge to find a hook that you can't see from the inside or outside and strong enough to be able to hold the weight of a substantial wreath.  This hook is perfect - even the sticky portion is clear so you barely see it from the inside of the house.   I highly recommend it!