Emission Labs PX4-Mesh - Parret ParThe EML PX4 mesh tube is equivalent to the 15 Watt Version of the historic PX4 by OSRAM and MARCONI, apart from the heater current. The EML PX4 has higher heater current. Since the historical data sheet gives no numerical value for Gm and Rp under normal bias conditions, the values for Gm and Rp were extracted from the historical tube curves. Guarantee The first owner can register the tube at the Emission Labs website, to participate in the 5 years