Altadore Gymnastics has the best home-made floor bars I’ve seen.
Simply drop an old rail into “slots” on wooden block supports. Leave enough space to slide under a mat.
When I coach bars, every circuit includes a floor bar. Within a couple of months any girl can do at least 3 forward pirouettes in series. Some even do “giant full” (reverse pirouette to direct forward pirouette).
Personal pirouette “records” are posted on the gym wall.
Time spent on multiple pirouettes on low bar greatly improves handstand work on floor, beam and bars. It requires no spotting.
Caution — though handstand drills are quite safe — sooner or later one of the kids will hit the block supports. Make them responsible to cover supports with mats.
The longer the floor bar, the better. “Short” floor bars are much less useful.
Gymnastics Coaching.com 