This Asteroid watch band with curved solid end pieces perfectly fit SEI 63Mas - SEI Prospex SPB143, SPB145, SPB147, SPB149 with Dia. 40.5mm, the interpretations of SEI's First 62MAS models. Asteroid is a delicate contemporary watch band that combines classic and modern design by means of style, is a perfect blend of elegance and athletic brilliance. The Asteroid stainless steel watch band comprises seven moveable solid links with a smooth bending characteristic. Five tiny staggered flat polished beads constructed it in the middle and two chamfered brushed outer beads. Thus, a sporty classic look gets a surefooted upgrade and even more comfort in the Asteroid watch band. This well-built replacement watch band was assembled with screw-in adjustable details instead of flimsy pressure pins. Watch band is tapering to 16mm buckle width. This item includes one pair of FAT spring bars (Generic SEI Dia. 2.0mm spring bar) to ensure a more secure connection. Accompany with V-Clasp double lock buttoned diver's clasp. V-Clasp was made from solid 316L stainless steel with extra 6 micro holes for flexible fine tune length adjustment. Featured in V shape safety lock, streamlined form & chamfer edged design to give a more massive look. Chamfer double locks diver's buckle is ideal for a watch band with a thickness of approximately 3.5 - 5.0mm thickness. Another awesome aftermarket stainless steel watch band for 63MAS Dia. 40.5, 62MAS-inspired Prospex SPB line 200m models. Today replaces your SEI watch into this unique aftermarket bracelet.