SonarPen is the first analog smart pen for the iPad. Its supported pressure level is not predefined because it doesn’t contain an analog to digital converter that governs the pressure levels. SonarPen uses the iPad built-in ADC to do the conversion. Generally speaking, ADC in the iPad has higher resolution than the ones found in smart pens, which give more pressure levels. Although SonarPen detects more pressure levels, but we are not trying to play up the number game, so you don’t see us brag about it.