Kooymans primarily played a Gibson Les Paul, a Gretsch 6119, a Fender Stratocaster, a Gibson Marauder, a Gibson SG, a Yamaha SG2000, several BC Rich guitars, a double cutaway Gibson Melody Maker and a Gibson Firebird, with his primary amps being a Roland Jazz Chorus, a Vox AC30 amp, and a Fender Twin Reverb.
Kooymans frequently used a Gibson Les Paul, Gretsch 6119, Fender Stratocaster, Gibson Marauder, Gibson SG, Yamaha SG2000, several BC Rich guitars, a double cutaway Gibson Melody Maker, and a Gibson Firebird. His primary amplifiers were a Roland Jazz Chorus, Vox AC30 amp, and a Fender Twin Reverb.