They go by a few common names, depending on the style and use:

• Cord locks (most common)
• Cord stops or stoppers
• Toggle stoppers or spring toggles
• Lace locks (often for shoelaces)

These pieces tighten and hold drawstrings, paracord, elastic, or light bungee. You’ll find single‑hole and double‑hole designs in shapes like barrel, ellipse, or “bean,” sized to fit different cord diameters. When choosing, consider hole size versus your cord, plus material: plastic is lightweight with lots of color choices, while metal offers a sturdy, polished feel. Multi‑packs can be useful for bags, hoodies, and DIY projects.

The tips at the ends of drawstrings are commonly called:

• Aglets (traditional term for lace or cord tips)
• Cord end caps or cord ends
• End tips or ferrules

These pieces help prevent fraying, give a clean finish, and make threading through hoodies, pants, and bags easier. Options include plastic for lightweight projects and metal for a sleeker, more durable look. Some styles push on, others crimp or snap in. If you’re replacing tips, match the inner diameter to your drawstring thickness and choose a color or finish that complements your garment or gear.

A cord lock uses a spring-loaded mechanism to grip and hold a cord:

1. Press the top to compress the internal spring and open the passage.
2. Thread the cord through the single or dual holes.
3. Release to let the spring press the cord against the housing, creating friction.

This setup lets you slide to adjust and then hold position without a knot. Dual‑hole styles help keep two ends even; single‑hole styles are compact for one strand or a loop. Grip can vary with cord size and texture, so matching the hole size to your cord diameter typically offers more consistent results.

Pick size based on your cord’s diameter and how you’ll use it:

• Measure the cord across; that’s the diameter to match.
• Choose hole size just slightly larger than the cord for a dependable hold.
• Quick guides (approximate): shoelaces 2–3 mm; apparel drawstrings 3–4 mm; 550 paracord about 4 mm; light bungee 4–6 mm.
• Hole count: single‑hole for one strand/loop, double‑hole for two ends.
• Material: plastic for low weight and color variety; metal for a rugged, refined feel.

If you’re unsure, assorted multi‑packs or a couple of sizes can help you find the best fit for your project.

It’s a quick install with basic steps:

1. Remove or loosen the end knot so the drawstring can pass through. Keep aglets intact if they fit the hole.
2. Compress the cord lock and thread the drawstring through the hole(s).
3. Set your preferred length, then tie a small stopper knot at each end so the lock can’t slide off.
4. Test the slide to confirm it holds; adjust knot size if needed.

If the drawstring is too thick for the lock, a model with a larger opening may be more compatible. For elastic cords, gentle tension while sliding can help. Results can vary with cord texture and thickness.