ur machined buss bars are desgined around XS Power D3400, D3400R, D1400, D1600, S3400, S1600 and the lithium 15k. These give you the option to be able to add and subtrack batteries as you need with out needing to rebuild new buss bars. Also giving you muliple inputs/outputs for your power and ground. 
This listing is for the single battery options or if purchasing for mulitle batteries this is your beginning cap and end cap. For doing multiple batteries you will need to purchase seprately the modular section at the link below. 
This item is sold as a pair
 
http://skyhighcaraudio.com/sky-high-car-audio-buss-bars-modular-section-group-34/