Store › Micro Rear Arm Duplicator Image 1 of 3 Image 2 of 3 Image 3 of 3 Micro Rear Arm Duplicator $54.95 This tool will help you precisely duplicate and build rear working arms for your micro. Will duplicate arms from 10”-13”. Quantity: Add To Cart Added! This tool will help you precisely duplicate and build rear working arms for your micro. Will duplicate arms from 10”-13”.