i ws wondering if these were like the root trainers? i purchased some root trainers from Thompson & Morgan last year and really liked them. they set a great straight root system, and bought me time if i couldn't get the plants in the ground right away. i used them for pinon trees, fava beans, and corn. i see that they're in the states now, that Park's now has them...
http://www.parkseed.com/gardening/PD/6196