#define CANSPEED_100 9 // 100 Kbps
7 = 125 Kbps3 = 250 Kbps1 = 500 Kbps
1 VIN (+12V)2 GND3 CANH4 CANL
The point is that I don't want to throw money at a CANalyzer (most are extremely expensive, in my wallet's own words!) when I could/should be able to see traffic with my Arduino.
I use these for my auto projects