3/8 in. x 1/2 in. Push-In x Male NPT DOT Adapter, Composite
3/8 in. x 1/2 in. Push-In x Male NPT DOT Adapter, Composite
Sizes in This Series
Composite DOT push-in to male NPT straight adapters. Jump to another size or add it straight to your cart:
| Size | Part # | Price | Cart |
| 1/4 in. x 1/8 in. | 680402C | $3.80 | Add to cart |
| 3/8 in. x 1/2 in. (this page) | 680608C | $10.99 | — |
Overview
The Midland 680608C is a composite-body D.O.T. adapter joining 3/8 in. push-in air brake tubing to a 1/2 in. male NPT port. The glass-reinforced body shrugs off UV, road salt, and vibration while weighing less than brass, and the one-touch collet seats the tube in a single push. Meets D.O.T. and SAE air brake requirements.
Technical Specifications
| Manufacturer Part # | 680608C |
| Tube Size (Push-In) | 3/8 in. |
| Thread Size | 1/2 in. Male NPT (1/2 - 14) |
| Connection Type | Push-to-Connect x Male NPT |
| Pressure Rating | 145 psi |
| Temperature Rating | -40°F to 140°F |
| DOT / SAE | FMVSS 571.106, SAE J1131 |
Materials of Construction
| Body | Glass-reinforced composite |
| Collet / Grip Ring | Stainless steel gripper with O-ring seal |
Typical Applications
Connects larger 3/8 in. DOT air brake tubing to 1/2 in. NPT ports on truck and trailer reservoirs, valves, and manifolds where a lightweight, corrosion-proof fitting is preferred over brass. A good choice for exposed under-chassis runs.
Cross-Reference and Interchange
This composite DOT adapter cross-references to these competitor and industry part numbers: 268PPCDOT-6D, CDOT1468-6-8, KV2H11-37S, QL1368-6D, S768PMT-6-8. Replacing one of these? Match nominal size, connections, and rating, or send us your part number and we will confirm the interchange.
Sizing and Installation Resources
- Push-to-Connect Fittings Selection Guide
- NPT Thread Tightening: Turns Past Hand-Tight
- Pipe Size Reference Chart
- Teflon Tape vs. Pipe Dope
Frequently Asked Questions
Is the composite body DOT approved?
Yes. It meets FMVSS 571.106 and SAE J1131 for air brake service, rated to 145 psi.
What tubing does it accept?
3/8 in. OD DOT-rated nylon air brake tubing. Cut square and push fully in until it bottoms.
Does it need thread sealant?
A thin band of PTFE tape or pipe dope on the 1/2 in. male NPT threads is recommended.
What is the temperature limit?
-40°F to 140°F. Keep it away from high-heat zones where brass would be the better pick.
WARNING: This product can expose you to chemicals 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.