This is a new style 2 channel programmer specifically designed to replace the now obsolete Horstmann and Secure C27 without the need for rewiring. the replacment programmer is shown in the 2nd picture. You can simply fit this new programmer onto your old Horstmann backplate with no need to alter any wiring. Please note that the Horstmann c27 is a discontinued model and cannot be purchased new anymore, the programmer we have is a direct replacement for it. Please review pictures and ask any questions you might have, we are happy to help where we can. Dispatched with royal mail as soon as possible.