Holmegaard Kluk Kluk Decanter by Danish designer Jacob E Bang is named for the sound it makes in pouring and designed especially for a slow pour. Hand blown, clear glass lends the imperfect, bespoke look that these decanters are so sought after for.
 
Tall decanter has a round stopper and shortdecanter has a mushroom top stopper, which is more rare by my research. Vintage 1960's mid century barware at it's best. Priced and sold as a matching set of two. 
 
Measurements in inches:
Tall Boy 12.5" x 5"
Shorty 9.25" x 4"