Slidable valve
FIG. 1 is a bottom perspective view of a slidable valve showing my new design; 
     FIG. 2 is a bottom plan view thereof; 
     FIG. 3 is a side elevational view thereof; 
     FIG. 4 is a top plan view thereof; 
     FIG. 5 is a left end elevational view thereof; and 
     FIG. 6 is a right end elevational view thereof.