Full Ceramic (ZrO2) Bearings. (Set of 2, different sizes.) * Other sizes are also available. * A small discount will be offered for multiple purchases. ↓ Specifications: [Palm Cup Side] Size Standard: 623 (also known as 1030) Outer Diameter: 10mm Inner Diameter: 3mm Thickness: 4mm [Spool Shaft (Handle Cup) Side] Size Standard: 693 (also known as 830) Outer Diameter: 8mm Inner Diameter: 3mm Thickness: 4mm Examples of Compatible Reels: 22 Silver Creek AIR TW Stream Custom Alphas AIR TW (AIR TW only compatible with AIR BFS) 19 Alphas CT SV 19 Millionaire CT SV Alphas SV Alphas Finesse Custom 20 Tatula SV TW 19 Tatula TW All Tatula models (SV/TW/CT/CT TYPE-R/HLC/HD Custom/TW80) TD Zillion J Dream TD Zillion HLC/PE Fuego (Overseas Model) All PX68 models Gekkabijin AIR TW PE SPECIAL Ryoga SSS 17 Fuego CT HRF PE Special etc. * The above is for reference only, please confirm size compatibility at your own risk. It rotates most smoothly when used dry, but when installed in the spool system of a bait reel, a high-pitched "shhh" sliding noise may occur during casting. If this bothers you, apply an appropriate amount of oil. (It should quiet down a bit.) * However, because it is full ceramic (PTFE for the ball retainer), there should be no seizing like with metal cage & metal ball bearings, even in the spool rotation range of a bait reel (even when dry). In other words, it doesn't rust (even in saltwater) and is an ideal, maintenance-free bearing (at present) that doesn't require oiling, etc. (Recommended for "Tatula series" where oiling the side located inside the handle cup is difficult. Especially for the 14 Tatula, both bearings are clip-fixed, making replacement easy.) Being a non-magnetic material, it is also easy to install near the brake magnet. Please note that after installing in a reel, you may not be able to receive manufacturer warranty, so please do so at your own risk.