7f33ac1a_ecp_cc__Value_Notes
[Part] VR1 [Size/#] TO-220 [Value/Notes] 
This is a voltage regulator for the heater. The heater actually wants 6.3V (though anything between 6.0 and 6.6V should be fine), but this is an uncommon Vreg voltage, so use a 6V. Any LM7806 in TO-220 is fine -- make sure it can deliver over 330mA.
ecp.cc
Value/Notes