Key Features
Accurately monitors your model's G-Force
Monitors all 3-axes up to 8G

Threshold alarm
Overview
Now you can accurately measure the G-Force your model is pushing, up to 8Gs on 3-axes.

Modellers can accurately measure the G-Force on their models using either the 8G or 40G Aircraft Telemetry Model Monitor. Smaller models can be measured on all 3-axes up to 8G. For larger models, or for those just looking to see the G-Force effects on their aircraft (up to 40G on 2-axes), there's a 40G sensor. Both sensors feature a threshold alarm.

SPMA9585 Aircraft Telemetry 3-Axis Gforce Sensor: 8G

SPMA9586 Aircraft Telemetry 3-Axis GForce Sensor: 40G

PS
I need one for my MiG 29/ FA-18 to see at what G forces foamies are developing fatigue cracks 

Manual for more info here
http://spektrumrc.com/ProdInfo/Files/SPM9585-Manual.pdf