48 is removable to permit the randomly adjustable weight to be adjustably positioned on the main drive shaft 34 of the vibration element as more particularly described below a number of thumb screw clamps 60 are threadedly affixed to one or the other or both of the depending walls 28 and 30 for removably affixing the vibrator 10 to a screed board to utilize the portable lightweight vibrator 10 preferably it is mounted in the middle of a 2 u00d7 6 screed board up to 20 feet in length as indicated above the screed board may be wood aluminum or magnesium the vibrator 10 should be placed on the screed board so that the thumb screw clamps 60 are on the back side and the power cord 64 of the electric motor is on the right side as the operator is facing the vibrator 10 when attached to the screed board in this position the vibrator 10 will walk or pull the screed board toward the rough pour the vibrator 10 is installed on the screed board 12 simply by disposing the latter between the depending walls 28 and 30 of the housing 18 and by tightening the thumb screw clamps 60 securely the electric motor 50 then is simply coupled to a source of electrical power not shown by means of the power cord 64 the amplitude or strength of vibration of the vibrator 10 is easily and quickly adjusted by first unplugging the power cord 64 from the source of electrical power the rubber plug 48 then.