Then you are not talking about a standard Diamondback. You must be talking about the Diamondback Tactical 4-12x40 which does not include the sun shade or side focus. SWFA just had the SS Classics on sale again for $200-250. Made in Japan by Kenko. Fixed power but target turrets and built like a tank.
The 12x42s were just $200 with either MOA or MIL reticle. I got a 10x42 MIL-Quad during the last sale with a set of Butler Creek caps for around $217 delivered.
https://www.swfa.com/swfa-ss-12x42-t....html?___SID=U