I thought to post my experience with this product and hopefully save someone else time and money.
I ordered the Rootrainer Kit from Lee Valley. It just arrived this past week and after opening the package and examining the various parts, it is very cheaply made.
They give you what they call a frame which requires minimal assembly. The frame just consists of light plastic which is suppose to snap together easily. Not quite as easy as they represent. There is no bottom to the frame, so if your watering your seedlings, you definitely need to put the frame inside of another container. No top like you see on most seed starting setups.
The cells (books) are made of what I can only described as the material with ridges you would find in a cookie or cracker box/tin. VERY flimsy and no obvious way to snap the cell/book closed securely. They claim the cells/books are reusable but in my opinion, given the flimsy construction, they would only last 1 seed starting season. Just my opinion from the merchandise I received. Instructions are written on the back of the advertisement that is slipped into the packaging.
I thought I would experiment with these for vegetable and perennials since the depth was deeper on the cells. I'm still looking for this type of cell depth, heavier material. What I received is going back to Lee Valley. Just be careful when
purchasing this type of product from other sellers online as I know that several well known companies do sell what appears to be the same product.