You can convert your one-shot cable to two-shot with this adapter.
You don't need to buy the expensive two shot mode cable. If you have a hot sync cable with PC Sync, your can simply connect this adapter to your hot sync cable for using two-shot mode.

For example, with Phase One P series digital back to make shutter in two shot mode, shutters need to be fired twice within four seconds. The first release of the shutter with the button on the adapter activates the CCD, the second release from your camera shutter button takes the picture. (If the time limit of four seconds is exceeded, the camera gives a warning “beep” followed by a “ready” signal. If for some reason it is not possible to fire the shutter twice within the time limit, the camera will send a time-out error message to the screen.)

The connects of the adapter are PC Sync female and male.

If you require more technical information, such as compatibility details or the necessary cables, please refer to the LensMod website.

We've designed and made adapters out of resin with 3D printers.
So, the finishing and the quality of the surface are not commercial grades. 

** We are not selling whole set of two-shot cables, but only one piece of the adapter to convert for two-shot. 

We only accept US domestic returns and refunds if the adapter is not working with your equipment. 
International buyers will not be eligible for returns, refunds, and compensations of any international shipping costs and customs tax.
International buyers, please verify the compatibility of our product and your equipment before you purchase to avoid complications. We recommend purchasing through eBay due to their excellent shipping service. However, if customs fees or shipping times are excessive through eBay (typically 3-4 weeks), please contact LensMod directly to explore alternative shipping options.