$fn=100;

difference(){
cylinder(5,d=5);
translate ([0,0,1]) cylinder(6,d=4);
}
difference (){
    translate([-1,2.7, 2.5])rotate ([0, 90])cylinder(1.5, 1.5,1.5, $fn=100);
    translate([-1.1,2.7, 2.5])rotate ([0, 90])cylinder(3, 1.1,1.1, $fn=100);
    cylinder(6,d=4);
}