"The SIRT 110 Pro offers a metal slide with extra durability, and also makes the weight of the SIRT pistol very approximate to that of a real pistol, including ammo. The Student model has a polymer slide, making it approximately 4 oz lighter than a real pistol."
"SIRT 110 Pro Pistol R/G (Glock) Green shot laser -- Metal slide -- Realistic Weight"
"SIRT 110 Student Pistol R/R (Glock)
Red shot laser -- Polymer slide -- 4 oz lighter than real pistol"