Ngineering N8502 Series Little Bigger Sound Modules are a great solution for adding layout-based environmental sounds to your model railroad. Each Little Bigger Sound module has a pre-recorded sound effect and includes an 8-ohm 2-1/16′ 52mm speaker and a 1-1/2 watt amplifier - ideal for big sound effects such as thunderstorms. Audio output is considerably louder than on Little Sound Modules - great for use on layouts in noisy environments or on large scale layouts. Little Bigger Sound Modules work best on a clean (filtered) 12V DC power supply such as Ngineering No. 514-N3512A.WARNING: This product can expose you to chemicals including LEAD, which is known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov