Right now there are 24 deals from Amazon Resale, formerly Amazon Warehouse Deals, in Pet Supplies › Fish & Aquatic Pets › Aquarium Accessories › Aquarium Heaters & Chillers. These are inspected returns and open-box items that Amazon sells and ships itself. WarehouseHunter puts each one next to its current new price, so you can see what you save at a glance.

Brands with the most offers here: hygger, Fluval, Eheim, GloFish, HEAD, SEAOURA, SereneLife, Tetra. Every item is a one-off, so the stock moves all day and new deals keep arriving.