Airsoft Guns and Upgrade Parts Manufacturer

I Chih Shivan Enterprise ( ICS )
Taiwan base company. ICS is considered one of the "Big 3" manufacturers of airsoft guns (the others being Tokyo Marui, and Classic Army, respectively). Manufactures M4 Carbines, MP5s, and an AK-74M replica. In addition, they have also come out with the split gearbox design for their M4 series, in which the upper gearbox (which includes the cylinder and spring assembly) disconnects from the lower gearbox (which houses the gear assembly) for easier repair and upgrades.

http://www.icsbb.com/

Autumn Star Industrial Co., Ltd. (G&P Lazer Product)
Hong Kong based company that specializes in aftermarket upgrades and external accessories, also make a variety of high quality AR-15 series AEGs along with an M249 SAW Heavy Machine Gun.

http://www.gp-web.com/

Guay Guay Trading Co. Ltd. (G&G ARMAMENT)
Taiwan base company specializes in internal and external upgrades and accessories. G&G manufactures higher end guns as well as a mid-range "sportline".

http://b2b.guay2.com/

HO FENG INTERNATIONAL CO., LTD.
Taiwan base company manufacturing spring powered airsoft gun (Sprinnger), airsoft gas gun (GBB &NBB) and airsoft electric gun (AEG).

http://www.hofeng.com/

WA / GunNet

http://www.wa-gunnet.co.jp/