This excellent quality 2 in Super Sprouter? Ultra Clear Vented Germination Dome fits standard 10 x 20 in propagation flats. Use the 2 in tall dome for germinating seeds or for small clones. Two vents in the top of the dome can be opened or closed to control humidity. These are the most clear and transparent domes on the market, allowing for maximum light penetration and the best viewing of your plant starts.