Both the kids can tie their shoes but they don't remain that way for long. Even when my wife or I double tie them for them, they still often come undone. I figured I would give these a shot and picked up one pair in a size 30 for testing purposes. I put them on a child's sized 13 1/2 tennis shoe. That size works well and I am glad I didn't order the 26 I had thought about as I wouldn't have been able to hit the last eyelet and still have room to tie them off. My son thinks they are neat and picked up on how to use them very quickly. I will likely be ordering  a few more to outfit a few other of their shoes (need some other colors as well). Also think it is  neat concept and will be picking up a pair for my own use. Only con is they are a bit spendy (They actually cost more then the shoes I put them on since I got those on clearance). My hope is though they will last over time and I can get them on a few pairs in the next year or so. I would recommend.

Edit: 12 weeks on my sons regular school shoes now and the laces still look good and (knock on wood) the plastic ends still attached. Shoes look beat up but again laces OK. Ordered a second set and put them on my daughters shoe as well. Hers are a shoe size one and again the lace size 30 worked fine.