Testing MTU - not getting correct results

[Puer Aeternus]

Hi all,
When in command prompt and I want to learn about my MTU size and ping yaoo, I am not getting the correct result (see image below). I am expecting to see what is fragmented and instead I get:
Bad option 1

 

[RJARRRPCGP]

Looks like "-1" doesn't exist. Try "-l 1492" (lowercase L)