Each CFL Recycling Kit can hold up to 13 13-watt CFLs and comes with a pre-paid return shipping label. The re-sealable VaporLok bag allows you to safely collect spent CFLs. When the box is full, seal it and place it in your mailbox. Sign up for "My Green Activity" and we will email you a Certificate of Recycling that confirms your bulbs were responsibly recycled.