The Bird Barrier Optical Gel Zip Pack (tf-bg55) is an accessory that enhances the use of Bird Barrier Optical Gel. This transparent disk can be placed onto irregular surfaces such as trees, indoor water sprinkler systems, gazebos, outdoor restaurant dining areas, or any tubular building feature. With an easy-to-use system, simply place the disk on any irregular or tubular surface then zip-tie it to secure its placement. Can be removed and reapplied at your convenience, only costing the zip-tie. None of the mess and discoloration caused by bird-repellent glue. Available in a pack with 25 disk bases and 25 zip-ties. Optical Gel NOT included.