This ignitor is the "narrow" style used by Trane and American Standard. The ceramic block on this ignitor is 1-1/4" wide, 1-3/16" deep, and 1/2" thick on the edge without the ridge. There is a locating ridge on the top right corner of the ceramic block when viewed from the wire end. The heating element portion if the ignitor is 2-1/4" long. The lead wires are 5-1/4" long and are terminated with a plug that has two male pins inside a plug housing that has two "D" shaped plastic prongs and two latching claws on the sides. This connection style was used on many Trane and American Standard furnace models. Two high temperature ceramic wire nuts are also included and can be used if your existing plug is damaged or is not long enough. This ignitor is the replacement for Trane and American Standard part numbers B340039P01, IGN34, and IGN00034.