The HMR-14B wide raw silk hammer was created to imprint the "raw silk" design on curved fluted surfaces.  Both faces are slightly domed rectangles.  If you're working on a concave product you might want to consider the HMR-14A.  Fretz casts their hammer heads from 420 stainless steel and tool hardens them to 50 HRC. The handles are made from oiled hardwood shaped and weighted to balance the head perfectly. Made in Vietnam. 

Head length 74mm

Handle length 220mm