Added pictures and specifications to KS-1580 Kershaw Boa
The Big, beefy Boa was the first knife to offer knife users Kershaw’s innovative, even easer, way to deploy the SpeedSafe® assisted opening system. The Boa lets the user pull back on a protrusion on the back of the blade with his or her index finger – using either the left or right hand. This short pull deploys the SpeedSafe® system so that the blade moves into position smoothly and locks into place. In addition.with the blade in the open position, the protrusion becomes an extended finger guard for additional safety and a secure grip. The Boa also features a thumb-stud that can be installed on either the right or the left side – making it even easier for left and right-handers to use the knife.
More information here:
http://www.1sks.com/store/kershaw-1580-boa.html