https://www.ebay.com/itm/373475305433  For those who remember these , I bought them  and not for the asking price !! I messaged the seller after the listing was dead for a week or so and told them their asking price was WAY too high and made an offer of which they accepted !! I went and picked them up today . I got as follows : approx. 12- GE 1000w PS-52 incandescents of which about 1/2 are either high hour or EOL ,  1 Daycoa 750w R-52? SBMV , 3-EYE 750w BT-46 Deluxe white SBMV , 3- Daycoa 750w BT-46 Deluxe white SBMV , and last but NOT least , 3 Daycoa 750w BT-46 CLEAR SBMVs !! 

Nice! I vaguely remember this listing being posted about a year or so ago. Glad to see you got and looks like there's a lot of BT-46s too.

 The BT-46's are all 750w SBMVs !! including clear !!

Tim, are the clear ones 120V? 

 Yep ! Have you ever heard of Daycoa ? The etch looks a lot like a Dura test etch . So far , one of the Daycoa coated lamps seems to be a dud as it looks to have had a air leak which smoked the filament ballast on run up !    Hopefully all of the clears are good !!

Nope, never heard of them. It's possible that these are indeed Duro-test lamps branded for another company, or this could be a Duro-test brand...
Hope the rest are good!

 I'm currently testing them as we speak ! The coated Daycoa's seem to have a color similar to a /C lamp  while the EYE version seems to be more of a warm color like a WDX .

What unusual lamps!  I wonder if the Daycoa lamps were made by Westron, back at the time when they made their SBMV lamps in New York prior to the 1970 relocation to Canada.

Yeah the packaging in the ebay listing definitely looks like westron.

When I 1st saw the listing I assumed that's what they were .

UPDATE !!  All of the SBMV's have been tested . Out of 11 750w SBMV lamps , 1 was confetti when I got them ( DAYCOA 750w R-52 ? ) I still have one of these intact !  All 3 of the EYE coated lamps work fine . 2 of the 3 DAYCOA coated lamps work fine , (one suffered an air leak and went up in smoke !)  2 out of 3 of the DAYCOA CLEAR lamps work fine . The 3rd looks absolutely perfect but does NOTHING !! Both filaments look fine , bimetallic sw. looks fine , all connections look fine but nothing happens !! Lamp also shows NO continuity unlike the remaining working examples !! DAMN IT !!