Ring Macan, Inner Diameter 23mm, Clear, Pack of 10 The Ring Macan with a 23mm inner diameter easily fit over the tension rod. This product was purchased and is Made in JAPAN. I bought these for lace curtains. They hold the curtains securely, and no adjusters are needed. The clear color is unobtrusive, and I'm happy with the pack of 6. There are various curtain rings, but I recommend these for tension rods. I bought a lot, but I can't use them all, so I'm selling 10 of them together. Thank you!