This is a T-shaped perch (with fastener) with a diameter of 15mm. It is mainly used by attaching it to the entrance of a hand-tame cage. It seems better for parakeets than a 12mm diameter perch. It can also be used with GB hand-tame cages. Size (approx.): Diameter 15mm, 105x60mm Washer size: 1.5mm x diameter 25mm For those who want it, we will give you 70g of hulled oats, which our parakeets love, as a bonus. If you want it, please say "hulled oats please."