Wide Application: Applicable to all kinds of rabbit cages, chicken cages, duck cages, pigeon cages, quail cages, parrot cages, rat cages and other pet biological cages. Easy to Use: Suitable for left or right hinge door, fixed with spring, convenient for cage opening and closing. Pull ring design, preventing pets from escaping. Package Includes: 5 pieces spring cage door . Sizes: length measures 45mm/1.77", ring diameter 20mm/0.79" for both sizes. High Quality: These metal finger spring are of high elasticity, and the whole surface is galvanized, more durable.