ORIGINAL: Wclays
http://www.xtremepowersystems.net/products.php?cat=19
The TattleTale is a tiny and lightweight device that plugs into a empty receiver channel (or through a Y-cable). This device measures the input voltage and displays the lowest voltage threshold that was captured after being powered on. With a programmable acquisition time of 10ms to 100ms, even the shortest voltage sags can be detected!
This is super small and gives alot of infromation. I have found this very helpful with my jets and planes
Clay
At 1.75 grams,
some may be against the high wing loading, 'extra baggage' their extremely heavy jets have to carry.

Check the density altitude at your field before using these products. [8D]
Like Dennis said... "It's just more stuff to fit in".