Depending on your experiences, you may know this as an Electrician’s knife, or a Lineman’s knife. Both are correct. Officially, it’s a 1978 Klein 1550-4 Hawkbill Slitting Knife. It has wood grain plastic handles and a clip ring (for hanging from the lineman’s bag or tool belt). The single blade locks open.

Spec's:
Blade Length: 2-5/8” (67mm)
Blade Steel: Carbon steel
Overall Length Closed: 4” (102mm)
Weight (oz.): 4.0

A part of my telephony tool kit since 1978, this old friend sold in November, 2012 for $40.00.