Openscad can be found here https://openscad.org/

Openscad source

sliderWithMax =40;  // [80]

	difference() {
		union() {
			linear_extrude(height=1.4)
				difference() {

					hull() {
						circle(d=6,$fn = 100);
						translate([sliderWithMax-2,0]) circle(d=4,$fn = 100);
					}

					translate([4,0]) for (i=[0:sliderWithMax/2-3]) translate([i*2,0]) circle(d=1,$fn = 100);
				}
			cylinder(d=6.7, h=3.8, $fn=100);
		}
		translate([0,0,-1]) cylinder(d=2.5, h=3.8+2, $fn=100);
		translate([0,0,-1]) cylinder(d=4.7, h=1+1, $fn=100);	
		translate([0,0,3.8-2+1]) cylinder(d=4.7, h=2+1);	
	}