Audio transformers for small radios use different materials each time, so they are subject to the existing ones when shipping. Mind the buyer need to contact in advance to ask clearly, and then take a photo thank you. Otherwise the seller is not responsible.

Core size: width 15mmX height 11.5mmX thickness 5mm. Frame size: 8x9.7x10mm. This transformer is powered by 1.5V, and is used on the No. 1 battery radio. The input transformer is blue. The primary is 1 set of coils with a resistance of about 60 ohms. The secondary coil is two sets of coils with a resistance of about 2*. 30 ohm; red is the output transformer, the output transformer is auto-coupling, the primary is two sets of coils, the resistance is about 0.8 ohm*2, the secondary coil is a set of coils, connected to the speaker, the resistance is about 1-2 ohms.