STANDARD SIZE. 2" diameter and the diameter of the port is 1/2". Fits as a replacement for most window bird feeders. FOR HOLIDAY SIGNS AND WREATHS, BATHROOM and KITCHEN SINK CADDIES, TOWEL HANGERS and FLAG ORGANIZER. Easy to attach and remove. Sticks on any smooth window, ceramic or mirror with a soft push. EASY TO REUSE - FOREVER! Just dunk in warm water for 2 minutes and the cups are as good as new! 4 clear, super strong silicone cups for your shower, holiday decor, sponge and soap holder and more. BEST QUALITY. Heavy duty, industrial suction strength. Perfect for your birdfeeder, plant hangers, aquarium accessories, bathtub caddy, wreath and more. LIFETIME GUARANTEE - We are so confident in the suction cups quality that we offer a lifetime warranty to all suction cup purchase. Decorations will stay on your windows in the sun, rain and snow. Amazing suction abilities for a variety of products