Purpose: ASK-ABK100 is a Chroma Key Processor Description: Two key sourse of input video ,two background of input video,four output video Supply six Tvsystems: NTSC3.58 ,NTSC4.43 ,PAL,PAL-M ,PAL-N,SECAM Your can select two key method: Phase key R,G,B can be keyed away by phase dajustment Luma keying R,G,B,Black,White can be keyed away by luminance level adjustment. Plug and play, easy to install.