Abstract: In the capillary tube 22, the cross section of the outer surface is substantially square, and the cross section of the insertion hole 23 is substantially square. Sides La, Lb of the outer surface have high dimensional accuracy and the insertion hole 23 is made to allow two optical fibers 5, 6 to be inserted while adjoining each other and arranged in order therein. The phases of the outer surface and the insertion hole 23 are relatively offset with each other, so that angles &thgr;a, &thgr;b which the sides 23a, 23b of the insertion hole 23 form with flat surfaces 22a, 22b of the outer surface are acute angles of substantially 45°±0.5°. Consequently, the flat surface 22a becomes substantially parallel to the center line M that connects the centers of the cores 5a, 6a of the two optical fibers 5, 6 inserted in the insertion hole 23, and the flat surface 22b becomes substantially perpendicular to the center line M.

Abstract: A golf club shaft has a grip portion at which the shaft is to be fitted with a grip, and a tip at which the shaft is to be connected to a club head. The grip portion of the shaft and the neighborhood thereof are made of a composite material comprising a fiber-reinforced synthetic resin layer and a metal layer, while the remaining portion is made of a fiber-reinforced synthetic resin.

Abstract: A golf club grip has a double-layer structure comprising an inner layer and an outer layer aminated on the outer surface of the inner layer. One of the inner and outer layers is made of a first material, while the other layer is made of a second material. The first material has an elasticity which is higher than that of the second material so that the first material is more readily elastically deformable than the second material, while the second material has a viscoelasticity which is higher than that of the first material.

Abstract: Disclosed is an improved putter whose head and grip weighs 320 to 360 grams and 100 to 260 grams, respectively. The total weight of the head and grip ranges from 445 to 585 grams. The grip-and-head weighting according to the present invention has the effect of improving the rolling of the ball to extend the rolling-and-running distance of the ball; and improving the stableness and directionality of the swing.