A weight of 200g would be about right and they are frangible i.e. designed to deform and cause minimal injury should one land on the head of a member of the public. Either way, they will not leave a black mark on an aircraft in the event of a collision. Rocket sonde payloads are a different matter but that's for another day.
Basil, I assure you the chap on the paraglider wasn't me
