Marine (boat) shops in my area carry Collinite 845 and 915. Maybe they carry this in your area as well? I have both products. Buy one, use for a a very long time. You will make your profit 100x over and your clients get outstanding protection for many many months.
I'm a bit surprised to hear a marine shop carrying 915 --- meant primarily for darker color cars, and isn't as long lasting as 476/885.
Collinite has done a better job getting their products into marine stores than auto stores, so if you're looking for an OTC purchase, call the boating stores in your area. Shipping from AG isn't too bad, so consider ordering from them to support AG since they provide us with this forum & expert advice.
As an FYI...After talking to my local Collinite distributor who worked in the factory for 12 years, comparing MSDS, then confirming directly with the factory via phone call, here is the mapping between auto & marine products. ...half a batch of wax can go into auto bottles & the other can go into marine bottles.
Auto / Marine
476 / 885 (Paste wax, no abrasives ; Longest lasting wax made by Collinite)
845 / 925 (liquid wax, no abrasives; Insulator Wax aka Fiberglass Boat Wax; Not as long lasting as 476/885 or 915, but will still last longer than most other waxes on the market)
915 / no marine # (Paste Wax formulated for extra shine for dark cars. Should last longer than 845, but not as long as 476. I heard a rumor that all the Collinite employees opt for the 476 over the 915, but there is market demand for the 915, so they continue to make the 915.
126 / 870 (Liquid AIO Cleaner Wax)
840 / 920 (Liquid Cleaner. Collinite does NOT suggest applying this to dark color clear coat paint. Autogeek does NOT recommend applying this to ANY clear coat paint)
850 (dual marketed as single #) - Metal Wax
855 (dual marketed as single #)- Liquid Leather & Vinyl Wax
I've used the 885/476 & 845/925 on both boats & cars & I have been extremely satisfied with both. It is more work to get the 476/885 out of the can & onto the pad. The 845/925 spreads extremely easy. Just remember to put Collinite products on very thin.
The 920 also did an excelent job cleaning mud off boat fiberglass + cleaning shower stains that have been around for years.