SNOW VIPER ON NORTHERN VIPER: Marines from 1st Marine Air Wing refuel an AH-1Z Viper attack helicopter at a Forward Arming and Refueling Point (FARP) during Exercise Northern Viper. Photo taken January 25 in the Yausubetsu Training Area, Hokkaido, Japan. Here’s a background post on the AH-1Z (published in 2011).

From the 2011 post:

Basically, the AH-1Z is created by remanufacturing older AH-1T/W attack helicopters into AH-1Z models. This produces a helicopter with a 10,000 hours (in the air) airframe, new engines, new electronics and an updated and much more effective gunship. There have been some problems with the fire control system (which is, when it works, similar to what the latest AH-64s have), that caused some delays. However, the marines were able to catch up, and the AH-1Z kept to its scheduled entry into service this year.

The AH-1W was an upgrade of the Vietnam-era AH-1 Cobra.

UPDATE: Link problem fixed.