KAISERSLAUTERN, Germany -- When it comes to Air Force physical fitness training, reflective belts are out and black socks are in. Hot-pink cell phones are now OK too, while in uniform, as are morale T-shirts and patches -- but only on Fridays.

Changes in what airmen can and cannot wear while working out or while on the job are spelled out in a revised Air Force instruction governing dress and appearance. The service on Monday announced the updated policy, which went into effect Friday.

Air Force Chief of Staff Gen. Mark A. Welsh III approved the changes, many of which were based on suggestions from airmen made directly to him during base visits or gleaned from comments to the service's uniform survey board, Air Force officials said in a news release.

Some of the changes are driven by a desire to recognize airmen's experiences, qualifications and job performance, allowing them "to wear what they have earned," said Col. Patrick Doherty, director of Air Force Services.

Other changes were made with heritage, team building, esprit de corps and unit pride in mind; the rest were "common sense approach inputs" from airmen in the field "that senior leaders thought were great ideas," Doherty was quoted in an Air Force news release as saying.

The revised policy eases some previous restrictions on airmen while in their physical training uniform. The requirement for reflective belts, for example, during physical training has been lifted, though commanders have discretion to order otherwise.

Socks are still required, but they can be black -- before only white socks were allowed -- and airmen may wear any color athletic shoe with their PT uniform.

Morale T-shirts and patches representing individual squadrons that were worn in the past to increase unit pride are now authorized for wear on Fridays, according to the new policy.

Earned Air Force qualifications badges, such as the Scuba Badge, Weapons Instructor Course Graduate Badge and Distinguished Pistol Shot Badge, along with other services' qualifications badges, such as the Army's assault and diver badges, are now authorized to wear on the Airman Battle Uniform (ABU), while the command insignia pin is mandatory.

The ABU has become primarily an in-garrison uniform, as airmen deployed to Afghanistan now wear the Army's camouflage uniform, Air Force officials said. That transition, coupled with airmen's "long-term desires to wear the qualification badges and the command insignia they have earned, makes authorized wear on the ABU a logical step," Lt. Gen. Sam Cox, Air Force deputy chief of staff for manpower, personnel and services, said in a statement.

Other changes include the authorization to use handheld electronic devices of any color while in uniform, as long as they are not worn on an airman's belt or waistband or clipped to a purse. All others must be plain black, silver, dark blue or gray, according to the policy.

Airmen at Ramstein Air Base said Tuesday some of the changes, like easing of the reflective belt rule during PT training, are common sense.

"There's enough reflective material on the uniforms," said Staff Sgt. Parrish Moore, a fitness assessment cell personnel member with the 786th Force Support Squadron.

Moore said he likes the new black-sock rule "because I don't ever wear white socks and it's weird to go buy one pair of white socks just to do the PT test," he said.

Staff Sgt. Lindsay Rhodes, a flight medic with the 86th Air Evacuation Squadron, thought the "black sock change is silly," but she likes having the option of choosing bright-colored athletic shoes "because it's a morale thing," she said. "It adds color to the blue and grey uniforms."

Stars and Stripes reporter Josh DeMotts contributed to this story.