SainSmart is well known and provides high quality electronics product
SIZE : 85mm*32MM*60MM
Input voltage : 3.5-30V
Output voltage: 0.8-29V (adjustable) output must be lower 2V than input
Conversion efficiency: 92% (test on 24V to 12V 2A)

Technical Details

Size (LWH): 5.6 inches, 5.3 inches, 2.1 inches
Product Details
Product Dimensions: 5.6 x 5.3 x 2.1 inches
Shipping Weight: 0.3 pounds (View shipping rates and policies)
ASIN : B00TJVNS78