8539.29.20.00 - Lamps having glass envelopes not over 6.35 mm in maximum diameter and suitable for use in cystoscopes and other surgical instruments

This HTS category, 8539.29.20.00, specifically classifies lamps featuring glass envelopes with a maximum diameter not exceeding 6.35 mm. The defining characteristic of these lamps is their intended use in specialized surgical instruments, such as cystoscopes, where compact size and precise illumination are critical. These are typically filament lamps designed for specific, low-voltage applications within the medical field.

Distinguishing this category from its sibling, 8539.29.10.00, is the intended application. While 8539.29.10.00 covers Christmas-tree lamps, this category focuses exclusively on lamps for surgical instrumentation. The other sibling, 8539.29.30, encompasses a broader range of "other" filament lamps not otherwise specified, making the precise fit and surgical application crucial for classification under 8539.29.20.00.

As this classification is a leaf node, there are no further subcategories. Therefore, classification hinges on meeting the stated criteria: filament lamp, glass envelope with a maximum diameter not exceeding 6.35 mm, and demonstrable suitability for use in surgical instruments like cystoscopes. This ensures accurate segregation of these highly specialized miniature lamps from more general lighting or decorative filament lamps.