BilletBox Gen 2

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Please read ordering information and FAQ BEFORE placing an order!


Click Here for Full Spec Flyer 


Quick Specs:

-100% Designed, Engineered & Manufactured in the USA

-100% CNC Machined from US Domestic 6061-T6511 or 7075-T651

-Optimized for Siegetek Gearsets

-Compatible with all “TM SPEC” receivers **

-Stainless Steel Spring Guide - Black Oxide Coating for wear resistance

-Stainless M3x.5 Torx button head cap screw hardware

-Quick Change Spring Guide comes standard

-Spring Guide retention screw standard

-Large AOE Alignment window

-Large Wire channels with retention under motor shaft area

-Undercuts provided for retention of springs during assembly

-Fully Radiused Cylinder window

-Ports for greasing / lubrication

-6061 or 7075 Aluminum variants available

-8mm or 9mm Bearing / Bushing variants available

-Type II Anodized - Clear / Grey Finish on initial release

-Backed by our Industry leading 3year manufacturing defect warranty


**Protech Airsoft cannot guarantee any specific fitment due to manufacturers constant changing design and

Manufacturing specifications. Customers who wish to verify fitment can send their receiver set in for test

fitment prior to purchase. For more information, please email


Ordering Information:

In order to keep the cost of the BilletBox as low as possible during the initial release, the ordering process will be as follows:

  1. Place your order via the website, select the material and bearing option you would like
  2. Payment will be taken in full at the time of placing the order – this ensures your order will ship as soon as it is available – paypal will not be an available method for payment for BilletBoxes.
  3. The weekly cutoff for all BilletBox Orders is Sunday, at 8PM PST – Orders placed after this time will likely be placed on the next production schedule
  4. You will receive an email Monday afternoon confirming your order, options, and estimated shipping date. This shipping date will range between 2-3 weeks. Many Billetboxes may ship sooner than this, but this is the expected time period. Once your order is confirmed, you cannot change, cancel or modify it without prior authorization from US. If you need to change your customization, contact us via email immediately.
  5. We will Machine, inspect, anodize and perform QC checks on your gearbox to make sure it upholds our extremely high standards.
  6. Your Gearbox ships to you or your favorite Co-Op retailer.
  7. You get the highest quality gearbox, Made In the USA!



Q: Why do I have to Pre Order this product?!

A: In order to better gauge what material and bearing options our customers want, we will producing these in small batches at first. This ensures we don’t overproduce, leading to extra expense to our customers

Q: 6061 or 7075? What is the difference?

A: Good Question. There are benefits to both. The short answer is that 6061 will be fine for most AEG builds, and will outlast any cast gearbox on the market, and most of the other inferior gearboxes made from unknown material sources. 7075 is a harder Aluminum alloy, this makes it stronger, but more susceptible to fractures / cracking. We have tested both the 7075 and 6061 gearboxes in builds up to 600+ FPS w/.2g.


Q: Can I order this from one of my favorite retailers?

A: Yes, many retailers will be ordering and carrying these. If your retailer is not already a dealer for us, please have them contact us to setup a dealer account.


Q: Will you offer additional Colors or a split-type gearbox?

A: Yes, We will offer both; however there is no ETA at the moment. For most configurations, a single clamped gearbox offers a better fitment and performance.