The main difference is how they seal: a lug cap uses short, interrupted threads (lugs) and locks on in about a quarter turn, while a continuous thread (CT) cap uses a single unbroken thread that needs several full rotations to tighten. Lug caps are built for high-speed capping lines and vacuum-sealing hot-filled products like sauces and preserves, whereas CT caps suit manual or machine application for non-pressurized contents. Lug caps are applied at a set torque and can strip if over-tightened; CT caps can be tightened fully without that risk. Evergreen supplies both closure types in tinplate steel.

A lug cap is a metal closure that seals glass jars and bottles using small metal tabs (lugs) that engage grooves on the jar's threads, so it opens or reseals with just a partial quarter turn. It's used mainly for hot-filled and vacuum-sealed foods — jams and preserves, pickles and fermented foods, sauces and condiments, and canned fruits, vegetables, and baby food — because it withstands high-temperature filling, pasteurization, and sterilization while holding a secure vacuum that extends shelf life. The cap is inherently tamper-evident, giving a visual or audible "pop" when the seal is first broken, and button-top styles (RTB) add a safety dome that stays depressed while the vacuum holds. Evergreen produces lug caps in tinplate steel from 30mm to 100mm — including regular twist-off, fluted, and button styles — with food-grade, BPA-NI, and PVC-free liner options.

A continuous thread (CT) cap is a metal screw closure with a single unbroken thread that spirals onto a matching threaded bottle or jar, tightening over several full turns for an easy-open, resealable seal. CT caps handle both vacuum and non-vacuum packed products and are common across food and beverage — jams, edible oils, juices, and carbonated drinks — where the threaded design extends shelf life while staying easy to open and reseal. They're made in tinplate or aluminum and paired with a liner matched to the contents — PE foam, plastisol, or pulp — so the closure seals reliably across a range of fill types. Evergreen supplies CT caps in sizes from 18mm to 89mm with CMYK printing and embossing options.

Both are sized to the container finish they fit, but they use different notation: lug caps are called out by diameter in millimeters plus the lug style (for example, "82mm standard lug" or "38mm deep-skirt lug"), while CT caps use a two-number code such as 38-400. In a CT designation like 38-400, the first number is the diameter in millimeters and the second is the GPI thread finish — 400 is a shallow, roughly single-turn finish, while higher numbers such as 410, 415, or 425 indicate a taller finish with more thread engagement. Evergreen supplies lug caps from 30mm to 100mm, including deep-skirt versions, and CT caps from 18mm to 89mm, matching each closure to the exact container finish.

Most metal food closures are made from tinplate steel, chosen for its strength, rigidity, and ability to hold a vacuum seal. The inside of the cap carries a sealing compound or liner — often a food-grade resin — and many suppliers now offer BPA-NI (no BPA intentionally added) and PVC-free liner options to meet consumer and regulatory expectations. Aluminum is sometimes used but is less rigid and generally unsuitable for vacuum food applications. Evergreen supplies tinplate closures with food-grade, BPA-NI, and PVC-free liner options.

Yes — metal closures made from tinplate steel are recyclable through standard steel recycling streams. Because both lug caps and CT caps are predominantly steel, they can be recovered alongside other metal packaging. Choosing recyclable metal closures supports sustainability goals without sacrificing seal performance or shelf life. Evergreen also offers sustainable material options across its metal, glass, and plastic lines to help brands meet recyclability targets.

Yes — metal closures can be decorated to carry a brand's colors, logo, and finish, turning a functional cap into part of the package's shelf identity. Common options include multicolor printing, embossing and debossing, and premium finishes like hot stamping or matte coating. Decoration applies to both lug caps and CT caps, so the closure can match the jar or bottle rather than read as an off-the-shelf part. Evergreen offers CMYK printing, embossing, debossing, hotstamping, and matte coating on our metal caps, so brands can align the closure with their wider packaging design.

Metal closure quality is verified through checks on seal integrity, removal torque, coating and liner coverage, vacuum retention, and dimensional accuracy against the container finish. Because application torque, headspace, and compound curing all affect whether a closure seals, testing covers both the cap itself and its performance on the actual jar or bottle. Evergreen conducts in-line compatibility testing on all production lots to catch defects before filling, protecting shelf life and reducing rejected product.