Ring with inner diameter 50 mm.
Fits the linked shells below:
Samsung
iPhone
Vario universal adapter
The Kowa eyepiece ring fits:
20-60x zoom TSN-600/660/82SV
20-60x zoom TSN-820/820M (blue metallic eyepiece, discontinued)
15-45x zoom TSN-553 Prominar
45xW TSN-600/660/82SV (discontinued)
Other eyepieces the ring fits:
Opticron HDF zoom 20-60x
Swarovski 20xSW ATS/ATM 65/80 (discontinued)
Swarovski 30xSW ATS/ATM 65/80 (discontinued)
Swarovski 45xSW for ATS/ATM 65/80 (discontinued)