These Lambretta rear hub locking rings (suitable for Series 2, CASA and Scootopia safe hubs (fits into the recess) and series 3 hubs) have 3 holes as standard but o ne hole is central, as on standard locking rings, the other two are off-set - one to the left and one to the right , allowing you to be able to tighten your rear hub nut without compromising how much torque you use as one of the holes in the ring WILL line up with the hole in the hub.
 
I have been using one of these since 2012 and have had no problems, the washer is a nice and tight fit on the rear hub nut, and sits perfectly flat on the hub. At 3mm thick it is more than up to the job!
 
It is professionally polished and will fit on any series 1, 2 or 3 Lambretta. 
These are professionally mirror polished, not seen very well in the picture, but will be super-shiny!
A really good price for a superior product, made with U.K. stainless steel in the U.K - Buy British!
 
Price includes VAT @ 20%