Z2-S is brand new, the A2 is older and in excellent shape.
Z2-S
Features
Virtually indestructible LED emitter regulated to maximize light output and runtime
Strobe for tactical applications
Precision micro-textured reflector creates smooth, optimized beam
Coated, tempered window resists impact and thermal shock, maximizes light transmission
High-strength aerospace aluminum body, Mil-Spec hard-anodized for extreme durability
CombatGrip for secure hold in all conditions
Tactical tailcap switch—press for momentary-on, press three times rapidly for strobe, twist for constant-on in either mode
Weatherproof—O-ring and gasket sealed
Includes high-energy 123A batteries with 10-year shelf life
Specifications
Max Output 160 .0 lumens
Tactical Runtime* 2 .0 hours
Length 5 .0 inches
Bezel Diameter 1 .25 inches
Weight w/Batteries 4 .9 ounces
Batteries 2x123A
$100 shipped