The Manitou Nixon Super Plus SPV Evolve 145mm is a lightweight trail bike fork. 
The SPV (Stable Platform Valve) is a special valve originally designed for rear shocks that helps reduce that up and down "bob" motion.
The SPV valve located on top of the right leg (red ano.) gives this fork a snappy feel.  Expect XC race like performance, yet long enough travel to hit up slope style stunts.
The left leg holds the air spring chamber.
Fully tunable, the Nixon Super Plus offers external damping adjustments, but doesn't have a lock out or travel adjust ride height.
The Nixon forks have:  1 1/8" size steerer tube.  They also accept "post mount" style disc brake calipers (74mm) only.
20mm axle only (bolt on style).  This fork is not compatible with standard quick release drop outs.  You need to use a 20mm through axle, DH style, front hub.