Radial: The mounting interface (threaded or flanged) is located on the side of the case, perpendicular to the dial,

 making it suitable for front or top mounting on equipment and for front-facing reading. 

Safety and Explosion Protection: Dual protection — Safety type 

(prevents injury from shattering) + Explosion-proof type (flameproof / intrinsically safe, prevents ignition of external hazardous gases).