The Guitar Speedle can accommodate numerous string through body types. Here they are categorized under 2 of the most common styles.
Staggered Body holes: (Schecter, ESP, Jackson, Etc) This style is great but has certain facets that cause the strings to get caught inside the guitar. Using the Guitar Speedle allows for a smooth insertion of the string. ( In rare cases, some guitar parts might be painted or may not have been installed properly during factory set up. If this is the case, the Guitar Speedle might not be able to fit comfortably through these holes )
The Strat/Tremolo bridge: (Fender, Ibanez, Charvel, Etc) This style bridge has saddles on which the strings sit. These saddles can move when not being held down by the string. This causes the screw holding them in place to turn causing the intonation of the guitar to change. This can be quite a nightmare. Using a Guitar Speedle not only helps guide the string through the guitar but it also keeps the saddles in place.
How to use the Guitar Speedle
From the front of the guitar, insert the needle end of the Speedle into the ferrule/saddle.
From the back of the guitar, insert the string into the Speedle and push through until it appears at the front of the guitar.
From the front of the guitar, extract the string and remove the Speedle.
Finish stringing as usual.