1. The small head probe made from plastic, the handgrip made from aluminium. 
2. Dimension A, dimension b and dimension C are (106 ± 0.5) mm, (145 ± 0.5) mm and (126 ± 0.5) mm, respectively.
3. Radius Rd and radius Re are (40 ± 0.5) mm and (53 ± 0.5) mm, respectively.
4. The diameter of the handgrip is (30 ± 0.5) mm.
5. The length of the handgrip is more than 100 mm.
6. The centre of the end of the handgrip have one M6 thread. The depth of the threaded hole is more than 8 mm.