Based on an r210 II I’m currently doing up

• Orico HB-325 3.5 to 2.5 inch Hard Drive Caddy - don’t even bother. Could be useful in a CRU sled, but I don’t have a dell one to hand.
• SilverStone SDP08B 3.5" to 2 x 2.5" Drive Bay Converter Getting better, but all four screws don’t align in the dell caddy
• SilverStone SDP08B, 3.5" to 3 x 2.5" Drive Bay Converter Absolutely perfect.

random info I thought may be useful to others