This could be the one? Tough to find 18 mm within US cheap...
Find many great new & used options and get the best deals for Sky High 10" Dual Showerhead Bubbler Tobacco Bong Hookah Water Pipe - Blue + Red at the best online prices at eBay! Free shipping for many products!
www.ebay.com
Also in green:
Sky High 10" Dual Showerhead Perc Bubbler. 1x 10" Dual Showerhead Perc Bubbler - Green Accenting w/ Black Logo. Sky High 10" Showerhead Bubbler Tobacco Hookah Water Pipe -Clear + Orange Camo. Sky High 8" Palmtree Matrix Tobacco Glass Water Pipe Bong Bubbler Hookah - Clear.
www.ebay.com
And clear:
Find many great new & used options and get the best deals for Sky High 10" Dual Showerhead Bubbler Tobacco Hookah Water Pipe - Clear + Black at the best online prices at eBay! Free shipping for many products!
www.ebay.com
This cheaper one also claims to be 18 mm though it's hard to tell for sure:
Find many great new & used options and get the best deals for 8.27" Clear Glass Hookah Water Pipe Showerhead Perc 18mm Quality Glass at the best online prices at eBay! Free shipping for many products!
www.ebay.com
Mostly just ash catchers here:
Get the best deals for 18 showerhead glass at eBay.com. We have a great online selection at the lowest prices with Fast & Free shipping on many items!
www.ebay.com
but you could pair with a hook...
(side note I am really liking the heady octopus ones actually!)
This one has extra neck perc (from SunshineStore on DHgate) but it is a nice removable 18 mm shower head too:
Find many great new & used options and get the best deals for 10.2" Heady Glass Pipe Bowl Bubbler Water Pipe Bong DFX Showerhead Percs 18mm at the best online prices at eBay! Free shipping for many products!
www.ebay.com
However if you really want nice 18 mm shower head shipped within the US, this would be your best bet though it cost more there are big discount codes:
Or this one too:
Here's another two although I despise matrix perc for vaping:
Check out Thick Ass Glass's 13 inch super slit matrix bubbler today. You can't go wrong with our high-grade products! Order today.
www.thickassglass.com
Check out Thick Ass Glass's 12" Super Slit Matrix Diffuser. You can't go wrong with our high-grade products! Order from Thick Ass Glass today.
www.thickassglass.com
This one is not exactly shower head, but looks nice:
Thick Ass Glass supplies a wide variety of products and accessories. Check out our 12 inch single ratchet bubbler today!
www.thickassglass.com
And cheapest, to go 14 mm:
These could be decent too:
Water Bong - 1. Percolator: Matrix Showerhead. Joint Size: 14 mm. 14mm Glass Bowl - 1. Color: Clear + Blue.
www.ebay.com
Does it have to be sold in Canada? Or are you just looking for something shipped to Canada... I would suggest skimming backwards through the thread?
...
Separately, check out this wild attempt at a recycler lol
We reveal our newest bong The Smiler. Featuring dual perc for max filtration.
www.ebay.com
Oh and hey this ashcatcher has the hammerhead shower head perc:
Find many great new & used options and get the best deals for 14MM CLEAR GLASS WATER PIPE ASH CATCHER CLEAR HAMMERHEAD PERC 45DEGREE at the best online prices at eBay! Free shipping for many products!
www.ebay.com
And actually this looks pretty sweet:
OCTOPUS 8" Water Pipe Bubbler Bong KRAKEN Glass Beaker Hookah Percolator Tobacco. Percolator - Maxtrix Showerhead perc. Includes glass bowl and Stem. Ice Catcher. Includes glass bowl 14.4mm. Hand Made Glass W Percolator Filter.
www.ebay.com
Simple sprinkler perc...
And these are pretty reasonably priced for US heady, especially if on sale:
- Simple Bubbler - 14mm Joint - Clear with Color Accent - UFO Perc
planetcaravansmokeshop.com