Fromeco makes the TNC tach. I sort of like the older model better but the new one is top of the line.
http://www.fromeco.org/Shop/aTNC%20Tach.htm
The tach sold by Horizon under the Hanger 9 label is less expensive but still has worked good for me. I've tried several Glowbe's and the hobbicoo but they are not worth carrying home. You really get whay you pay for in this catagory.
JMHO from hands on use.
FEB