The MODULITH SL20 combines on-line ultrasound and optional X-ray in series. In addition to highly simplified patient positioning and the possibility of handling the machine as a multipurpose lithotripter for disintegration of urinary-, gallbladder and bile duct stones and for treatment of pancreatic concrements this appliance can be used in cases of sialolithiasis and as a workplace for all urological purposes, so that the design is very modern. As the energy level in f2 can be extremely high, a disintegration rate of about was achieved for 70% ureteral stones in the middle and distal sections of the ureter. However, this good disintegration rate was not achieved for ureteral stones lying in the upper ureter or in cases of nephrolithiasis treated with a prototype of the machine. In our opinion, this reflects a problem with nonexistent on-line X-ray stone localization, but an overall disintegration rate of about 77% in preselected patients (1.8 stones/patient) confirms that this is a highly sophisticated and powerful machine.