Blue Line BLM005 Performance Microfiber Jock Strap for Men

What it is

The Blue Line BLM005 is a men's microfiber jock strap, sold in black and in white. It is built on the classic jock cut: a smooth, seamed front pouch joined to a broad elastic waistband, with two elastic leg straps running from the base of the pouch around the hips to the back of the waistband, leaving the seat open. Blue Line packages it in a slim black carton printed with the brand wordmark, a jock strap line drawing, the size, and the word "Microfiber" down the spine.

It sits in the men's clothing range rather than among accessories — this is underwear you wear, in a style that has been in continuous production for roughly a century and a half.

Fabric and construction

The fabric is microfiber, which is the one material statement Blue Line prints on the carton. Microfiber is a catch-all term for synthetic filament spun finer than one denier — finer than a strand of silk — and then knitted into a dense, fine-gauge fabric. That construction is why microfiber garments feel slick rather than fuzzy against the skin, drape closely, and carry very little bulk under clothing. The BLM005's pouch is cut from a single smooth panel with a curved seam at the base, so there is no gathered fabric at the front.

The waistband is the part you notice first. It is a broad woven elastic band carrying a set of fine horizontal stripes through the middle of it. On the black version those stripes read as deep red, grey and white; on the white version the same banding appears in grey and muted red. A small woven brand tab sits on the front of the waistband, just right of centre. The leg straps are narrower elastic of the same family, joined to the pouch at the bottom and to the waistband at the back.

There is no fly, no lining panel, no pouch opening and no hardware — nothing to fasten, adjust or break. The whole garment is three pieces of knit and elastic sewn together, which is most of the reason the style has outlasted every underwear fashion that came after it.

A note on where the style came from

The jock strap is usually credited to the 1870s, when a Chicago sporting-goods maker produced a pouch-and-strap garment for the men who rode bicycles over Boston's cobblestone streets for a living. Those riders were called bike jockeys, and the garment took their name. The basic geometry has barely moved since: pouch at the front, band at the waist, straps around the back. What has changed is the material. The originals were cotton webbing and canvas; the BLM005 is the modern reading of the same pattern in fine synthetic knit.

Product specifications

How to wear it and look after it

Step into it as you would briefs, draw the waistband to your natural waistline, and settle the leg straps so they sit along the crease where the thigh meets the seat rather than riding up across it. The pouch should hold without pressing; if the waistband rolls or the straps slide, the size is wrong rather than the cut.

Fine elastic and fine knit both dislike heat. Wash cool — by hand, or on a gentle machine cycle inside a mesh bag so the straps do not tangle with heavier items. Skip fabric softener, which coats synthetic fibre and dulls the way microfiber handles moisture, and skip bleach entirely on the black version. Hang or lay flat to dry. A hot tumble dryer is the single fastest way to kill the stretch in an elastic waistband, so leave it out of the machine.

Who it's for

This suits an adult man who wants minimal underwear, either for the gym and sport, where the style originated, or simply because he prefers an open back under trousers. The flat microfiber and low-bulk pouch make it a reasonable choice under close-cut clothing. It is also a common first jock strap, partly because it is a plain two-colour design with no mesh panels, cut-outs or hardware to think about. Browse the rest of the men's range if you want to compare it against trunks and briefs.

It is less suited to anyone who wants full rear coverage, or who wants a pouch with a contour panel or a separate lining — the BLM005 is deliberately a plain one.

Good to know

• Sold for adults 18 and over.
• Synthetic knit and elastic. If you have a known sensitivity to elastane or polyester-family fibres, check the garment's own sewn-in label on arrival.
• Underwear is a personal item, so please read the store's returns terms before ordering if you are unsure of sizing.
• Orders ship in plain outer packaging with no product imagery and no adult-themed wording on the label.

Frequently Asked Questions

What is the Blue Line BLM005 made of?

Microfiber — that is the fabric Blue Line prints on the carton spine. Microfiber is a dense knit of very fine synthetic filament, which is what gives the BLM005 its smooth hand and low bulk. No percentage breakdown of the fibre blend is printed on the packaging, so if you need the exact composition, check the sewn-in label inside the garment when it arrives.

What colours does the BLM005 come in?

Black and white. Both are the same cut and the same striped elastic waistband; the stripe colours shift slightly between them, reading as red, grey and white on the black version and as grey and muted red on the white one.

How is a jock strap different from briefs or a thong?

A jock strap has an open back — there is no fabric across the seat at all, just two elastic straps running from the pouch to the waistband. Briefs cover the seat fully, and a thong covers it with a narrow strip of fabric. All three share a front pouch, so the difference is entirely behind you.

What size should I choose?

Pick your size from the size selector on this page. Blue Line sizes this style in combined bands rather than single waist measurements, and no measurement chart is printed on the carton, so if you are between sizes, the elastic waistband is the part that has to fit — go by your usual underwear size rather than your trouser size.

How should I wash it?

Cool water and no tumble dryer. Hand wash or use a gentle machine cycle in a mesh laundry bag, leave out the fabric softener and the bleach, then hang or lay flat to dry. Heat is what degrades elastic, so keeping the BLM005 out of a hot wash and out of the dryer is the main thing that keeps the waistband holding its shape.

How will this be packaged when it ships?

Orders go out in plain, unbranded outer packaging. There is no product photography, no brand name and no adult-themed wording printed on the outside of the parcel or on the shipping label.

Product information compiled and reviewed by the Gear Isle product team. We transcribe product specifications directly from manufacturer packaging. Found an error? Tell us.

These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease. Adult novelty device for adults 18 and over. Consult a licensed healthcare professional before use, especially if you have a medical condition. Keep out of reach of children.