Besides the quality of the processed steel, the first-class workmanship and surface finish, and safe sterilization, there's one particular reason for the ongoing popularity of SEIRIN needles – their particularly gentle insertion qualities
Many experts agree that the first puncturing of the patient’s skin should be painless or at least nearly painless. In contrast to other, mainly Chinese needles, SEIRIN needles come very close to this ideal.
Painless insertion of the needle is primarily achieved by quick penetration of the upper layers of the skin (cutis). Compared to other tissues, the cutis is densely interspersed with pain receptors. The chief pain is caused as the upper skin layers are penetrated, whereas the subcutaneous tissues are comparatively insensitive to pain.
SEIRIN needles are very easy to handle, particularly sharp and have an extremely thin silicone coating at their tip (SEIRIN permanent needles come uncoated). This allows for quick and easy puncturing and facilitates certain needle techniques (e.g. very point).
(Ref. to: Marcus Bäcker; Michael G. Hammes; Akupunktur in der Schmerztherapie; ELSEVIER 2005)