In case number of lubrication points to be fed are many i.e. more than 12 nos. It is advisable to use master block as primary feeder. Lubrication line from master block shall be connected to secondary block from where lubrication points are joined. The discharge of master block is more than the secondary block. Master Block has pressure indicating pin in each line. In case of over pressure, pressure indicating pin comes out. This happens when the line coming out from the master block get chocked.