You just selected:
HEATER: HEAT.WAV, 4KW, 2'', 2PSI, M-CLASS
Code Gecko
9920-100346

HEATER: HEAT.WAV, 4KW, 2'', 2PSI, M-CLASS
Heater for M-CLASS / MSPA / 4kW
You should also consider these companion products:

TSC-4-GE1 AND OVERLAY
Code Gecko
0200-007119

TSC-4-GE1 AND OVERLAY
K-8-SL-GR-ADB-PPD(Replaces BDLTSC8GE1 and BDLTSC8GE2)
Code Gecko
0200-007194

K-8-SL-GR-ADB-PPD(Replaces BDLTSC8GE1 and BDLTSC8GE2)
PRESSURE SWITCH 2PSI (replaces 510AD0167)
Code Gecko
510AD0249

PRESSURE SWITCH 2PSI (replaces 510AD0167)
Continue shopping