New From PondMaster, Air diffusers. 

Available in 3 styles, 

Sup14570: Straight 6 inches Use with 1/2" or 5/8" tubing. 

Sup14575: Straight 6 inches  Kit with 20 ft of 5/8" tubing. 

Sup14580: Round 7 inches diameter Use with 3/4" or 1" tubing.