You put your right leg in...
934633
Length on these is off by 1.  Ordered another pair and got the right size!
3641704
I am a wider guy and when I rode my bike, my knees were jutting out to the right and left as I peddled.  Over time my knees were really bugging me.  I went to the Physical Therapist and she had me bring my bike in to show her.  One look at me peddling and she told me to get a set of these.  It totally fixed my alignment.

Cautions:
1)  Know that bike pedal threads are different on left and right side.  Make sure you put the right extender in the right side.  They do come labeled.  Check internet for how to videos if you are not aware of this.
2)  Install with a little grease on all threads
3)  Since your pedals are out further from center.  If you turn sharply with your inner foot depressed you may scrap your pedal or worst wreck.  This only happens if your crank arms are long and your tires are short..  But I did clip a pedal once and wrecked when I turned coming up the sidewalk at a curb cut
4730429
It's tight and it gives you the feeling of your feet being clamped. The heel is not as soft as expected.
3813031
The bladder you put over the arm is connected, it's wierd.
1472129
I got the item with something wrong with its legs. it was not balance (i mean it can't stay)... arm and head joint are so hard to move....
2275963
Great product. Easy to assemble, if you carefully read the instruction. Make sure that you pick one leg from the left package and the other from the right, so that you can combine them. Otherwise, your chair will be very unstable.
3976019
No direction. Went back to Amazon write-up and saw to place it between thighs or below knees. I have knee and lower back pain so opted for between thighs. While trying to go to sleep had to keep repositioning it. Very uncomfortable. Apparently while sleeping I had to keep pressing thighs together to keep it in place so in the morning I had more pain than if I hadn't used it.
3262579
Perfect size wasn't too hard to set up.  On the bad side ..... I keep bumping my legs on the frame and it hurts.
4296070
This is a great exercise experience. I can really get a good heart pump and feel it in my legs
2059968
It's almost like you are standing directly on the ground.  Not the most comfortable, but nothing an insert cannot change
738863
Amazing ^_^ just love swimming in the monofin! I was taught to swim with my legs together (as odd as that seems) so this was just a way to help me get more speed behind me.
1440690
They came with the body of the legs separated from the waist band.  Don't have time to mess around sending back internet underwear I chucked em in the waste bin.  You win some you lose some.
2454528
Tried to use it as a seat cushion. It hurts your bum.  Now it just sits hmm.. not sure where it went. Oh well.
3533039
So simple!  All I had to do was screw the legs on, and it was ready to go!  Good quality material, and very comfortable.  And can't beat the price.
4183639
Not bad, but one of the rubber feet came off while adjusting one of the legs, and now the leg is stuck inside itself.
532107
careful with this.  I really hurt myself but I also blew off the advice about staying above your knee.
3831997
Like putting your feet in a little piece of heaven. Brava!! I have neuropathy and i search for comfort!! Ive found it im here to say, BRAVA!!!!