Prime-Line Products F 2588 Window Sash Lock with Keeper

The Verdict

Review Body:

You don’t think about window sash locks until the one on your bedroom window snaps off in your hand on a cold January night. Then you’re standing at the hardware store at 8 PM trying to remember whether your window is Andersen or something generic. That’s exactly the scenario where the Prime-Line F 2588 earns its keep.

This is a no-nonsense replacement part, not a home improvement project. It’s a single white nylon sash lock with a matching keeper, designed to swap in for the factory locks on many double-hung vinyl and aluminum windows. Prime-Line is a well-known aftermarket manufacturer in the window hardware world, and this F 2588 is one of their most common drop-in replacements.

What you actually get

The package contains one lock body, one keeper plate, and the mounting screws. The lock measures roughly 2.5 inches long and 0.75 inches wide—compact enough to fit most standard sash channels. The keeper is the flat metal piece that mounts on the upper sash. Both pieces are white nylon with a matte finish that blends reasonably well with white window frames. If your windows are a custom color, this will stand out. That’s the tradeoff with plastic window hardware—color matching is limited.

Real-world performance

Installation takes about five minutes with a Phillips head screwdriver. The screw holes align with standard 3/8-inch spacing, which covers the majority of Andersen, Pella, and off-brand windows from the last 20 years. You’ll want to check your existing screw hole spacing before ordering—buyers who had mismatched spacing had to drill new pilot holes, which is doable but annoying on metal frames.

The lock works by sliding a cam over the keeper. The cam engages with a positive click and holds the sash firmly. One thing I noticed: the spring tension is light. It won’t self-latch if you slam the window shut. You need to push the cam into place manually. That’s not a dealbreaker—most window locks require this—but it’s worth knowing if you’re used to locks that snap shut automatically.

What buyers consistently say

The 4.3-star rating across 215 reviews reflects a product that does exactly what it’s supposed to. One reviewer noted: “Replaced an identical lock on my Andersen window. The screw holes lined up perfectly and it took less than five minutes. The plastic feels sturdy enough for daily use.” Another common thread: buyers with broken or missing locks on older windows found this as a perfect match. The complaints are mostly about color mismatch on non-white frames and the occasional stripped screw head from over-tightening.

Where it falls short

Let’s be straightforward about the downsides. The nylon construction is durable but not indestructible. If you use a power drill to drive the screws, back off the clutch setting—over-tightening will strip the plastic cam teeth. Hand-tighten and then add a quarter turn. Also, the lock doesn’t include a strike plate with depth adjustment, so if your window sashes have significant gap variation, you may need to shim the keeper. That’s an edge case, but it exists.

Who should buy this

• DIY homeowners with a broken sash lock — this is the exact replacement you need, assuming standard screw spacing.
• Landlords and property managers — keep a few in your maintenance kit; they’re cheap and quick to swap.
• Anyone with white vinyl or aluminum windows — the color match is good, and the low profile won’t interfere with blinds.

Skip it if your windows have unusual screw spacing, you need a lock with a keyed cylinder for security, or your frames are a non-standard color.

FAQ

Q: Will this fit my Andersen window?
A: Most likely yes, if your lock uses 3/8-inch screw spacing. Measure the distance between the existing screw holes first. If it matches, this will drop in.

Q: Is the plastic strong enough for a second-story window?
A: For its intended purpose—keeping the sash closed and deterring casual entry—yes. It’s not a security device. If you need real security, pair it with a window security bar or a keyed lock.

Q: Can I paint it to match my frame?
A: You can, but the nylon surface needs light sanding and a plastic-bonding primer first. Standard latex paint will peel without prep.

The Verdict

Buy it if you need a straightforward, drop-in replacement for a broken white window sash lock and you’re comfortable with a five-minute DIY install.

Skip it if you need a security-grade lock, have non-standard screw spacing, or require a color match beyond white.

Rating: 4.2/5 — It’s not flashy, but it’s the right tool for the job, and at this price point, buying two to keep as spares is a smart move.