Prototyping board protobloc 1 rapid kh 102 p this prototyping board protobloc 1 breadboard is a prototyping system offering a fast and economical method of circuit construction and development solderless in concept allowing components to be used time and time again while components are plugged into the board and are retained by double leaf spring contacts p incorporating the following features protobloc prototyping board 2 29 x 5 grid size 390 number of holes 2 54mm hole pitch