Rack mount ReadyNAS drive caddy replacement/spares

Some information I've gathered to help anyone who's looking:

According to the Netgear hardware manual, the ReadyNAS 2120, 2120 v2. 2304, 3130, 3138, 3220, 3312. 3312 v2, 4220, 4312, and 4312 v2 all use the same drive caddy.  I have confirmed that a Chenbro RM13919-01B caddy will work in a 4220, so that means they should work in all the others. It looks a little different, since the original is a Chenbro RM13919-01C. Unfortunately, the -01B version doesn't seem to be a lot more available than the -01C. The -01D is more available and looks the same, but I don't have one to test.  There are some even older Chenbro models that look much the same but lack the 2.5" drive mounting holes. My guess is they'll all work. But if anyone knows for sure, please add to this topic.

I believe these were also OEMed to other manufacturers. The source of mine are that I bought some drives "with caddy", with the caddy brand unspecified, so I don't know the source brand of the server.  I had no use for them at the time, but the price of the drives was right and am not even sure why I held onto them.  But things sometimes just work out.

The older RN3200, RN4200, RN4200V2, and RD5200 use SuperMicro caddies, which are available under a variety of numbers on eBay, with 01-SC93301 being what I purchased.

With used rackmount ReadyNAS sometimes available without caddies because the former owner was too lazy to remove the drives from them before destroying them, this may help some wishing to acquire one.