On the Tour bikes

[Plum Hill]

What are the little black "things" affixed below the saddles on some of the bikes?
They're black and rectangular. They're not numbers. They don't appear to be transponders.
Contador had one on the bike he crashed but not on the replacement bike. Other bikes have them.
Noticed the same thing on some bikes at the Tour de Suisse.

[oldpotatoe]

What are the little black "things" affixed below the saddles on some of the bikes?
They're black and rectangular. They're not numbers. They don't appear to be transponders.
Contador had one on the bike he crashed but not on the replacement bike. Other bikes have them.
Noticed the same thing on some bikes at the Tour de Suisse.

Finishing dangles to keep track of who is where and how they finish. Like the thingy runners have on their shoes for running races.

[Plum Hill]

OK, but why did some of the TdeS bikes have that along with the normal chain stay mounted one?
See: http://keyassets.timeincuk.net/inspirewp/live/wp-content/uploads/sites/2/2016/06/WATSON_00004638-006-630x421.jpg
Numerous TT bikes had both; a number of regular road bikes did, too.

[BdaGhisallo]

Transponders.

[choke]

These? http://inrng.com/2015/06/geolocation-telemetry-dauphine/

[nooneline]

There are cameras and transmitters on some bikes. Is that what you're seeing?

[Plum Hill]

These? http://inrng.com/2015/06/geolocation-telemetry-dauphine/

Bingo!
Looks like that's it. The comment about being on trial explains why they were on bikes with standard chain stay-mounted transponders.
Thanks.