Description: Glass CO2 diffuser, durable as well as elegant, adding a beautiful scenery to your aquarium. This item will dissolve Carbon Dioxide (CO2) speedily into your aquarium or tank. High efficiency of diffusing carbon dioxide.Easily to install and use. Helps to ensure plants receive proper amounts of CO2, improve the growth and health of your plants with sufficient CO2 supply. Suitable for use as a decoration or provides a good source of aeration for the tank or aquarium. Specification: Material: Glass 20 gallons-Round Size: Approx.7x5x2.5cm/2.76x1.97x0.98in 28 gallons-Round Size: Approx.7x4.5x2.5cm/2.76x1.77x0.98in 28 gallons-3 spins Size: Approx.12.5x8.5x3.5cm/4.92x3.35x1.38in 28 gallons-5 spins Size: Approx.12.5x8.5x3.5cm/4.92x3.35x1.38in 28 gallons-8 spins Size: Approx.12.5x8.5x3.5cm/4.92x3.35x1.38in Package Includes: 1 Piece CO2 Diffuser(2 Pack) 2 Piece Suction Cups(2 Pack) Note: To avoid breakage when removing tubing, do not pull tubing off of glassware. Instead, cut tubing carefully along the attachment length to release the glassware. Mount your diffuser using the suction cup(s). It should be positioned low in the aquarium. When removing or repositioning the diffuser, pull by the suction cup(s) rather than the glass to avoid breakage.