It is imperative that your turntable is set up perfectly level. If the deck is not level, not only will tracking error and bias compensation be compromised, but the motor and main bearing will not perform optimally, causing wow and flutter as well as generating undesirable noise. In some instances, the platter is not absolutely level with the top plate of the turntable. In our view there is only one way to set the level, and that is by taking a reading from the centre of the platter, when an LP is in place. Anything else is a compromise. This is why we designed this one. The accurate 40mm diameter vial has a machined and polished acrylic base, with a centre hole for the spindle - allowing it to sit precisely where you need it to - the centre of the platter. You may see cheaper circular bubble levels advertised as turntable levels but unless they have a base allowing them to sit over the spindle, they are no use for turntables, as they have to be placed to one side of the spindle and (when an LP is in place) this does not give a true reading. Similarly tubular levels are a waste of space for this application. The standard model TSL is 60mm diameter, 19mm high and weighs 44g. It will accept spindles that project up to 11mm above the record label. If you have a longer than average spindle, you will need the Deep Base model - this will accept spindles up to 21mm above the record label, and weighs 76g. Please state which model you require when ordering - there is no extra charge for the Deep Base model, but you should only order this if your spindle requires it, due to the additional weight.