This Janome compatible 2 Pin Push In Light Bulb is very small at 24mm full length including the pins
fits the following models:

Janome: MC3000, MC4000, MC5000, MC5700, MC8000, MC9000,  MC11000, MC4800, 4030, J150, MC3500, XC33, 
MC10000, Compulock (888).