Black Holes Drippers Black Holes are a unique and innovative top feed dripper manufactured for use in hydroponic applications. 1/2" and 1/4" barb option. 1/4" barb is compatible with standard drip emitters by plugging them into the barb (rec. 2 GPH emitter). Designed with 6 beveled emitter holes and a raised flat at each one on the inside trough that together reduce clogging. 100% made in the USA with 100% recycled plastic. Lifetime leak warranty.