When buying SILENCIA earplugs in Japan, “S” does not mean smaller in every dimension, and an NRR label is not a promise of your personal sound reduction. Compare the exact names, measurements and restrictions before deciding whether either product meets your needs.[1][2][4]
I’m Irene, a Taiwan-born pharmacist qualified in Japan.
Sources checked on 24 October 2026, Japan time. This is a pre-purchase identification and label comparison for adult shoppers, not a wear test, noise-reduction test or insertion/removal guide.
Identify the two packs: both contain two pairs and a case
This table covers the official store’s サイレンシア® レギュラー (Regular, product code SLC-REG) and サイレンシア® Sサイズ (S size, product code SILENCIA S). Each contains two pairs of earplugs and a carrying case. Do not apply this table to other SILENCIA models or bulk packs.[1][2]
On a phone, scroll sideways inside the table. These are official measurements, not dimensions estimated from photographs.
| Check | Regular | S size |
|---|---|---|
| Official product code | SLC-REG | SILENCIA S |
| Contents | 2 pairs + carrying case | 2 pairs + carrying case |
| Material | Polyurethane | Polyurethane |
| Overall length | 25 mm | 22.0 mm |
| Diameter | 12 mm | 12.2 mm; 11.0 mm at the waist |
| Labelled NRR | 32 dB | 30 dB |
| Washing / swimming | Not water-washable; not for swimming | Not water-washable; not for swimming |
S is shorter, but not thinner throughout
S is 22 mm long, compared with Regular’s 25 mm. However, its listed diameter is 12.2 mm, not less than Regular’s 12 mm. S also has an 11 mm waist. “Shorter” therefore does not mean “thinner throughout”, and these external dimensions cannot establish which product fits an individual ear canal.[1][2]
NRR 32 and 30 are labels, not your personal reduction guarantee
The labels give NRR 32 dB for Regular and 30 dB for S. In its workplace-noise guidance, NIOSH explains that a packaged NRR may not reflect the protection each worker actually receives. Here, the figures are label comparisons only: do not subtract 32 or 30 directly from everyday noise levels or use them to rank personal fit or suitability for a workplace.[1][2][4]
NIDCD’s general hearing-protection guidance says that protectors do not block all sound. NIOSH also warns that overprotection can reduce awareness of surroundings and that communication needs matter. This does not mean an alarm or someone calling will necessarily be audible: NRR cannot provide that guarantee. These are general cautions, not alarm-audibility tests of these SILENCIA products.[3][4]
Check the restrictions and your needs before buying
Neither product is water-washable or intended for swimming. If washing or swimming is a requirement, these two products’ stated limits do not meet it. Do not borrow another model’s cleaning or use instructions simply because it shares the SILENCIA brand.[1][2]
NIDCD’s general earplug advice is that wearing them should not hurt and they should not be forced into the ears. A hearing health professional can help with selecting hearing protection; the name S or Regular alone cannot establish personal fit. This is not an insertion or removal procedure for either product.[3]
The package photos include “抗菌・抗ウイルス” (antibacterial/antiviral), “女性・お子さま” (women/children) and “安眠” (restful sleep). These phrases are not used here to choose a size by gender or age, recommend overnight use or promise infection prevention. This remains an adult pre-purchase comparison.[1][2]
Three checks before paying: match the full name and two-pair pack; read length, diameter and NRR separately; and check that your needs do not conflict with the non-washable, no-swimming restrictions. Before use, read the complete instructions and precautions supplied with your exact product. This article does not replace them or assess suitability for an individual ear condition.
