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PlanetBox Explorer lunch box shown exploded - stainless lid, teal silicone gasket ring, removable steel inner tray, and outer steel box with two steel latches

PlanetBox Explorer Leakproof Lunch Box Set

Recommended

A leakproof steel box that seals with a bare stainless lid and a drop-in silicone ring - no plastic lid frame anywhere in the seal.

The verdict: Silicone only

Everything structural is 304 stainless: the outer box, the removable inner tray, the lid, and both latches. The seal is a single silicone gasket ring that drops into the underside of the steel lid, and it is the only non-steel part in the box. That distinction matters more than it sounds. The usual way to make a steel bento leakproof is a plastic lid frame carrying a silicone ring, which puts a molded plastic face directly over the food; here the lid is bare stainless and the silicone does nothing but sit in its channel. The gasket lifts out for cleaning and is sold as a replacement part, so the one elastomer in the system is the one part you can renew.

Verification: Manufacturer confirmed · Last reviewed August 2026

What it's made of

PartMaterialFood contact
outer box
304 stainless; holds food directly when the inner tray is lifted out
Stainless Steel
304 / 18-8
Yes primary
removable inner tray
lifts out and is the only part of the set rated microwave safe
Stainless Steel
304 / 18-8
Yes primary
lid
bare stainless on both faces; no plastic frame or liner
Stainless Steel
304 / 18-8
Yes primary
lid gasket
LFGB silicone ring seated in a channel on the lid underside; removable and sold as a spare
Silicone Yes seal
latches
two steel over-center latches, one on each long side
Stainless Steel
304 / 18-8
No

PlanetBox's adult-sized box and the first in the line built to actually hold soup. It is a deep single-cavity steel box with a shallow steel tray nested inside, so you get a two-level pack rather than fixed compartments - lift the tray out for one big cavity, leave it in for a split. Two over-center latches pull the lid down onto the gasket. It takes Rover Dippers and Pods if you want more subdivision, and the lid face is magnetic for the decorative magnet sets. At 4.79 cups it is a full adult lunch, not a kid portion.

Pros

  • The removable inner tray is microwave safe, which almost no steel box can claim
  • Genuinely leakproof, so soup and dressings travel without a separate jar
  • Gasket lifts out for cleaning and can be replaced rather than binning the box
  • Two-level packing is more flexible than fixed compartments

Cons

  • Heavy at 1.2 lb empty, before food
  • Only the inner tray is microwave safe - the box and lid are not
  • Over-center latches take a firm hand; young kids will struggle
  • The gasket is a wear part and will need replacing eventually

Notes

Common questions

Does the PlanetBox Explorer Leakproof Lunch Box Set have plastic in it?

No petroleum plastic touches your food. On the PlanetBox Explorer Leakproof Lunch Box Set, the lid gasket is silicone, and the rest of the food path is stainless steel.

What is the PlanetBox Explorer Leakproof Lunch Box Set made of?

Part by part, the PlanetBox Explorer Leakproof Lunch Box Set is: outer box — stainless steel; removable inner tray — stainless steel; lid — stainless steel; lid gasket — silicone; latches — stainless steel.

Does the PlanetBox Explorer Leakproof Lunch Box Set have silicone in it?

Yes — the lid gasket is silicone on the PlanetBox Explorer Leakproof Lunch Box Set. It is a seal rather than a surface your food sits against, which is stainless steel.

Is the PlanetBox Explorer Leakproof Lunch Box Set BPA-free?

No plastic touches your food on the PlanetBox Explorer Leakproof Lunch Box Set — the food path is stainless steel and silicone — so BPA, which comes from polycarbonate and epoxy plastics, is not in play here.

Where is the PlanetBox Explorer Leakproof Lunch Box Set made?

The PlanetBox Explorer Leakproof Lunch Box Set is made in China.

Categories: Lunch Boxes

Sources

Every material claim above is backed by these. This is the scattered info we centralized.

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