Three of the tools have a T-bar handle (the fourth is a plain finger loop) for ease of use.Item A: two square prong for final output stage - Volkswagen Polo, Golf 1.4L, Caddy 1.4L, Bora 1.4 and 1.6L, Beetle 1.4L (from 2003), Lupo 4cyl direct injection (from 1999), Passat, Touran 1.6L, Phaeton and Transporter T4. Equivalent to OEM T10166.Item B: single sided square for coils with power stage - Volkswagen Bora, Golf, Passat, Phaeton, Sharan, Touareg, Touareg 6cyl (from 2003) and Transporter T5 6cyl with injection engine (from 2004). Equivalent to OEM T10095A.Item C: wide, shallow square for coils with final output - Volkswagen Eos (from 2006), Golf, Passat (from 2006) and Touran (from 2004); Audi A3 2.0 (from 2004) and A6 3.2 (from 2005). Equivalent to OEM T10094A.Item D: Extra wide shallow square for coils with final output Audi and Volkswagen injection engines. Equivalent to OEM T40039.