Sight Periscopic A.F.V. No1., MK.4

[Hanno Spoelstra]

Who can help I.D. this CANADIAN ARMOURED FIGHTING VEHICLES GUN SIGHT No1 MK4 Item number: 6625846043?
As far as I can tell it isn't a Sherman tank sight.

H.

Hello,

Can you tell me what models of Sherman tanks would have used the following gun sight, and are there operating manuals available to know how they worked? I recently won this tank sight on an ebay auction, and as I collect armoured corps items, I'd like to know more about it. Here is the ebay description:

A complete Sight Periscopic A.F.V. No1., MK.4. V.F. 207597 by B&S LTD.No 2107. Made in 1945 Canadian C broad arrow marked. Optics are in like new condition.

You may view this item in pictures by going on the ebay US site, using the number 6625846043.

Regards,
Patrick Johnson
Canada