From Amazon
Adam Hall 3 Star Series 3m 2x 6.3mm Jack Mono to 2x 6.3mm Jack Mono Audio Cable
Scan
3m Adam Hall Twin Channel Audio Cable 2x 6.3mm Male Mono Jack to 2x 6.
Conrad Electronic
Adam Hall K3TPP0300 Instruments Cable [2x Jack plug 6.3 mm (mono) - 2x Jack plug 6.3 mm (mono)] 3 m Black