mv engine cat sensors

[shakey]

Hi , can anyone please tell me what the two sensors, one at each end of the cat on my mv engine are. I have just replaced the old engine and want to remove the cat when i replace with a new exhaust system. I have had the pipe before the muffler fitted with a mounting for the sensor but need to know what they both do and can i remove the otherone completely.
cheers

[gti mad man]

erm bit vague but asuming one mayeb a lambda senser to work out the engines emissions/enrichment

[shakey]

one sensor definately lambda, but what is the second smaller unit and can i lose it

[jason k]

baxter sells a decat pipe.