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1.25mm pitch High-Reliability

Vibration and shock resistant,
miniature yet powerful.

  • 2 Amps per contact
  • Up to 150°C operating temperature
  • Secure latching system
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  • Specification

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Harwin’s Gecko (G125 series) connectors provide a low profile, dual row interconnect solution, ideally suited for stacking and cable mating in areas where PCB real estate is at a premium.


  • 2A per contact (all electrically loaded; 2.8A per individual contact)
  • 4-finger Patented* contact design to maintain electrical contact through high vibration and shock
  • Beryllium Copper Contact for improved temperature range: -65°C to +150°C
  • 1,000 Mating cycles durability
  • Weight and Space saving over Micro-D connector products
  • Future-proofed Materials - halogen-free, PFOS-free, SVHC-free and RoHS compliant
  • Low outgassing properties - 0.68% TML, 0.01% CVCM, 0.26 WVR (Water Vapour Recovered)

With space and weight a consideration for many high-reliability applications, Gecko delivers a pin spacing of 1.25mm, up to 50 contacts per connector. This design means that G125 connectors achieve a 35% space saving over other high-performance connectors such as Micro-D.

Overlay of Gecko v Micro-D

26-contact Gecko (green) overlaid with 25-contact Micro-D (red)

Gecko is a focus product for Harwin, and is undergoing an active development program. The connectors are designed with automated assembly systems in mind - all connectors can be purchased in Tape and Reel packaging.

* Patent Status:
Granted US9017089, Pending GB2501063, Pending EP2642604

Latched Connectors

The original Gecko range features latching mechanisms on the Male connectors, easy to release either by hand or with the Harwin-designed unlatching tools.

PCB Mount Connectors Female
  • Vertical PC Tail/Throughboard
  • Vertical Surface Mount
  • Vertical PC Tail/Throughboard
  • Horizontal PC Tail/Throughboard
  • Vertical Surface Mount
Cable Mount Connectors Female
  • Cable Contacts
  • Cable Housings
  • Cable Contacts
  • Cable Housings
Pre-Crimped Contacts
  • Female to free end
  • Male to free end
  • Female-to-Female
  • Male-to-Female
  • Male-to-Male
Complete Cable Assemblies
  • Female to free end
  • Male to free end
  • Female-to-Female
  • Male-to-Female
  • Male-to-Male

The following information is highlights from the Gecko performance characteristics. Download the complete Component Specification C125xx in PDF format for more detail.



Female Contacts High performance Beryllium Copper, Gold finish
Male Contacts Copper Alloy, Gold finish
Housing 30% Glass-Filled High Temperature Nylon (Polyamide) 4T, rated to UL94V-0
Latches Copper Nickel Tin alloy, Tin over Nickel finish
Cables PTFE Equipment wire
Potting Compound Stycast 2651MM with Catalyst 9



Current (at 25°C) 2.8A max per individual contact, 2A max all contacts electrically loaded
Working Voltage 450V DC or AC peak (250V DC or AC peak at 70,000ft/21km/44mbar)
Maximum Voltage 600V DC or AC peak (350V DC or AC peak at 70,000ft/21km/44mbar)
Contact Resistance 25mΩ max
Insulation Resistance 1GΩ min



Operating Temperature -65°C to +150°C
Humidity Classification 56 days at 93% RH
Vibration (with latches) 10-2,000Hz, 1.5mm, 198m/s² (20G), 2 hours total
Shock (with latches) 981m/s² (100G) in Z Axis, 490m/s² (50G) in X & Y Axis
Outgassing 0.68% TML, 0.01% CVCM,
0.26 WVR (Water Vapour Recovered)



Durability (contacts) 1,000 mating cycles
Durability (latches) 100 mating cycles
Insertion force (per contact) 2.8N max
Withdrawal Force (per contact) 0.2N min
Latch retention force (per mating pair) 20N min


Wire specification

Recommended Wire types BS 3G 210 Type A, MIL-W-16878/6 type ET or NEMA HP3 type ET
Wire Sizes 26 to 32 AWG
Insulation Diameter Ø0.80mm max
Strip Length 1.50-1.75mm
Component Specification (including pin numbering system) C125XX - G125 Gecko Connectors
Catalog pages Pages 1-12
Test Report - General HT030xx - Gecko General Testing
Product Training Module Gecko Overview
Outgassing figures Outgassing data list
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