Abstract: The invention relates to a hockey puck with a flat cylindrical body (1) of flexible elastic material. The aim of the invention is to provide a puck which is particularly suitable for playing hockey on hall floors or in the street and is as visible as possible during the game. This aim is attained in that the flat cylindrical body (1) consits of several disc-shaped segments (2, 3, 4) firmly bonded together, where a central segment (3) is made of a transparent material and has a recess for an insert with a light source (5, 6), a power source (7), a switch (8) and regulating and control components.

Abstract: A mechanism for adjusting string tension of stringed rackets allows for increasing the tension of the racket strings without having to release the racket strings, without destabilizing the racket and without costly or troublesome aids. The tensioning mechanism includes an abutment piece and a tensioning piece. Strings of the racket pass through both pieces. The tensioning piece is lockable in varying positions to increase string tension. When the racket is strung, the mechanism can be arranged in a position of least tension. In that case, if the string tension declines, the tightening mechanism can be adjusted to a position of the next highest racket tension. Alternatively, the mechanism can be initially set to a medium tension setting and subsequently adjusted as appropriate.

Abstract: The puck is provided in its center with a recess (2) to receive at least one light source (3), and light channels (7) are arranged leading from this light source (3) to its circumscribing surface (4) and/or to the edges of its two lateral surface (5, 6), said channels being filled with a highly transparent material.