SUKHOTHAI, Thailand - Jets zoom past and the earth trembles from artillery fire. The thunder of gunfire and explosions fill an entire valley. Four M117 Stryker Improvised Carrier Vehicles appear and quickly disappear through the clouds of smoke.

This is the Combined Arms Live Fire Exercise of Exercise Cobra Gold '09, an exponential display of air and ground forces capabilities.

The CALFEX is the culminating event of Exercise Cobra Gold 09, an annual joint multi-national exercise in its 28th year. Originally involving solely the militaries of Thailand and the U.S., the exercise has grown to include Indonesia, Japan, Singapore and a contingent of more than 15 observers from other nations.

The U.S. Army, Marine Corps, and Air Force teamed up with Royal Thai Air Force and Marine Corps to lead the CALFEX.

"The intent of Cobra Gold as well as the CALFEX and the fact that the Strykers are here is to advance the interoperability between the services, additionally, by having a live fire exercise, it fosters command and control of live rounds," said Lt. Col. Robert Bready, Cobra Gold liaison officer for the CALFEX.

The event began with close air support provided by U.S. Marine Corps AV-8B II Harrier Jets. The ground was hit with 81 mm mortars and 155 mm artillery rounds, followed by four Stryker teams who dismounted and cleared the objective with .50 caliber machine gun and small arms fire, backed by 200 Royal Thai Army Soldiers who swept the area one last time.

"We got to show the Thais the .50 cal and the use of the Strykers," said Sgt. Philip Hawlay, 2-23 Infantry, Stryker-108th Stryker Brigade, Fort Lewis.

This year is the first Cobra Gold CALFEX to include Strykers manned by a team of 50 soldiers from 4th Brigade, 2nd Infantry Division out of Fort Lewis, Washington.

"The Stryker goes a lot faster than any other vehicles that we have, it can get up to speeds of about 80 miles per hour, but it's got a lot of control so you get to the objective a lot faster," said Hawley. "Plus you get to carry a lot more men and it's a lot more comfortable for the men because you have a lot more room."

In order to prepare for the exercise, all involved had to run through a number of drills.

"For the past four days, we've been out here doing dry fires and blanks," said Hawley.

After the CALFEX, Lt. Gen. Benjamin R. Mixon, commanding general U.S. Army, Pacific, and host for Cobra Gold 09, visited the U.S. Army Stryker 2-23 Recon Platoon.

Mixon thanked the Soldiers, who recently returned from a tour in Iraq, for their service. He praised them for a job well done during the CALFEX and asked individual Soldiers what they had learned during the exercise.

"The capability we have is essential but it's the things you can learn from it that count," Mixon said.

"The Army is all about Soldiers," said Mixon. "Equipment is great, technology is great, that's what gives us the advantage, but what really gives us the advantage is the American Soldier. All of you that have the experience you have, and whether it's only a couple of years or a couple of tours in Iraq, that experience is invaluable."

Those involved in the CALFEX expressed satisfaction from the endeavor.

"We really had a good time out there," said Hawley. "Just to get to train with different militaries was an awesome experience."