AquaPro Transparent Glass CO2 Air Diffuser - Medium Part # 51067
 
Specs
Height - 7.5 cm  /  2.95276  or  2 - 15/16" 
Depth - 3 cm  /   1.1811  or  1 - 3/16"
Diffuser Plate - 1.6cm  /  0.62992  or  5/8"
 
Package includes 
One Diffuser
One Suction Cup
One Air Value