Grodan is a type of rockwool, it is a sterile and very versatile media with an excellent air to water ratio for optimal plant performance.  Grodan is very popular with tomato, Capsicum, Lettuce, Herb and other crop growers as it leaves no "gritty" bits in your salad.  These cubes measure 75mm x75mm x 100mm and are suitable for growing on of vine crops.  Each has a hole for seed placement. 

Sheets of multiple cubes can be placed on an Ebb and Flow propagation table for high density propagation.  After germination they can then be transplanted directly into an NFT channel, moved on into the larger cube for growing on, or placed into a growpot and surrounded with media such as pumice, scoria, or vermiculite. 

A box of Grodan each cube measures 75 x 75 x 100mm.  1 box contains 256 cubes.