These are replacement slider hooks for the Victoria or Julia flyers as well as the regular high speed flyer for all other wheels.
INSTRUCTIONS TO TIGHTEN SLIDER HOOKS
Remove the slider from the flyer. Position the pliers so that you have a secure grip on the wires. Gently squeeze the wires together, slowly ( if you squeeze too hard or fast you could break the plastic and they will pop out of the pliers).
Put slider back on the flyer, if it’s not tight enough take it off and squeeze again.