Find the exact refill family before comparing price

Two supported pairs

Pentel explicitly lists BL77 among models supported by its LR7 liquid-gel 0.7 mm refill. Its Handy-line S highlighter page names SLR3 refills, and the SLR3 page identifies SXS15 as the matching highlighter. These are two bounded manufacturer relationships. They do not establish that LR7 and SLR3 are interchangeable or that all Pentel products share one refill.

Use the finder narrowly

Our refill finder covers only these two observed body families. Select BL77 or SXS15 and the tool returns the corresponding documented refill family and source. Entering another model produces an unverified result. The finder does not use a similar-looking barrel, a shared 0.7 mm label or a brand name alone to make a fit claim.

What the finder cannot approve

A family match still leaves the selected refill color, pack quantity, condition and current availability to check. A worn or damaged pen body may also need attention outside a catalog fit lookup. We have not inserted the refills, modified a cartridge or performed a mechanical test. No cross-brand adapter or cut-to-fit procedure is provided.

Keep the old identity

Before discarding packaging, save the body model and existing refill identifier. Compare them with the exact current maker page and seller listing. If the body model is unknown, ask the manufacturer instead of buying from a guessed dimensions match. A cheaper cartridge that is not documented for the body does not become a useful purchase merely because its unit price is lower.

Do not confuse a color suffix

The selected black pen and refill include the suffix-A in BL77-A and LR7-A. The documented relationship is between their body/refill families; the color choice still belongs to the actual selected offer. Keep a different ink color or package quantity visible instead of treating a family-level match as a complete order specification.

A quick order sequence

Identify the body, open its maker relationship, select the actual refill color and count, then compare delivered price. If the first two steps are unresolved, record the refill as unverified rather than buying because its photo resembles the old cartridge. This sequence keeps a valid low price from answering the wrong fit question.

Before you decide

• Keep the exact selected SKU, color and selling unit
• Check current maker scope and the actual seller offer
• Separate your assumptions from measured performance