According to the size and hook, the lingual brackets can be classfied as following: Lingual Bracket0.022"/0.018"No Hook Item No: 1024-1Lingual Bracket0.022"/0.018"3#W/Hook Item No: 1024-2Lingual Bracket0.022"/0.018"1, 2, 3#W/Hook Item No: 1024-3 More Product Features Model NO.: 1024-1 Standard: 022/018 Company: Hangzhou Protect Medical Equipment Co. Ltd.