These are gate handles for tape electric fences.
There are 2 'T' shaped tape holds held side to side by a spring which holds the tape tight and flat right up to the handle. This keeps the tape flat making it look far neater than having it 'all scrunched up'.
The 'L' hook at the end allows it to clip into the gate handle insulator
without stretching the tape. This means that tape gate can be tighter when closed that when using handles with more rounded hooks. Because of this, the spring in the centre of the handle is more stiff to pull than most.