Kumpoo · string
JS-63 Sound Boom String
Specs last verified 2026-05-22 · $12 typical retail
Verified catalogue specs for the Kumpoo JS-63 Sound Boom String. Run the equipment finder to see how it ranks for your level and style — or read the full first-person review when we have one.
Specifications
- Brand
- Kumpoo
- Category
- string
- Price (USD)
- $12
- Evidence
- source only
- Last verified
- 2026-05-22
- Gauge
- 0.63 mm
- Feel
- medium
- Best for
- crisp sound, value, thin gauge
- Editor note
- Kumpoo JS-63 'Sound Boom' string — 0.63mm diameter, Made in Japan (rare for a Chinese-brand string). Build: multifilament strands + woven processing + core coating + side-filament coating. Sound character compared to Yonex XB63 at lower price. Source-only verification. Community reviewer reports better durability than expected for the thin gauge — 4 matches at 25-27 lbs tension without fraying.
Primary source: manufacturer page. See our methodology for verification tiers.