This is an American Made Oregonglassblower 18.8/18.8mm[19mm] glass on glass showerhead diffuser.  Six slots in end and 4 slots above for a total of 10 slots. Great addition for all 18.8mm Glass on Glass water pipes.
Your choice of length either 3, 3 1/2, 4, 4 1/2, 5, 5 1/2 or 6 inches in length. Measurement is from bottom of the male [lower] ground  joint to the bottom of the showerhead.Please refer to the measurement chart in the photo of the standard 18.8mm diffuser. 
Will work with Roor, PHx, Pure,Illadelph, Toro, etc. 
Be sure to let me know what length you need so I can ship it as soon as possible.           Please double check your measurement before ordering, thanks.  
I try to make all my orders the same day and ship out the following morning Priority mail [ 2-3 business days ]

$29 and $6 priority mail shipping.
I don’t make money on my shipping charges. I ship everything Priority Mail [2-3 business days] and shipping rates cost me about $6 before packing time and material.
Must be 18 or older to purchase.
Please purchase item ONLY if you intend on prompt payment as I am charged
sellers fees the moment you press the Buy Now or Accept Offer buttons. Thanks!