See attached photos for clarification.
This is also covered in each product's respective manual, which can be found on the following product web pages under the Documentation tab:
http://www.onsetcomp.com/products/sensors/s-rgc-m002
http://www.onsetcomp.com/products/sensors/s-rgf-m002
http://www.onsetcomp.com/products/sensors/s-rge-m002