Kodelåsen og hengelåsen er nye.

Because both nouns are in the definite singular form.

• en kodelås = a code lock / combination lock
• kodelåsen = the code lock / the combination lock
• en hengelås = a padlock
• hengelåsen = the padlock

For many Norwegian nouns, -en works like English the when the noun is singular and common gender.

In Norwegian, definiteness is often shown by adding an ending to the noun instead of using a separate article.

So instead of:

• the code lock
• the padlock

Norwegian uses:

• kodelåsen
• hengelåsen

This is very normal. English uses a separate word; Norwegian often uses a suffix.

They are compound nouns, which are extremely common in Norwegian.

• kodelås = kode
  • lås
• hengelås = henge/hengel-
  • lås

The last part, lås (lock), is the main part of the compound. It usually determines how the whole word behaves grammatically.

That is why the definite ending is added to the whole compound:

• kodelås → kodelåsen
• hengelås → hengelåsen

Er is the present tense of å være (to be).

A very important difference from English is that Norwegian verbs do not change depending on the subject:

• jeg er = I am
• du er = you are
• han er = he is
• de er = they are

So even though there are two things in the subject, Norwegian still uses er.

Because the subject is plural.

The adjective ny changes form depending on gender and number:

• ny = singular common gender
• nytt = singular neuter
• nye = plural

Here, the subject is kodelåsen og hengelåsen — two things joined by og (and). That makes the subject plural, so the adjective becomes nye.

Compare:

• Kodelåsen er ny. = The code lock is new.
• Huset er nytt. = The house is new.
• Kodelåsen og hengelåsen er nye. = The code lock and the padlock are new.

Because each noun refers to one item:

• kodelåsen = the one code lock
• hengelåsen = the one padlock

Together, they form a plural subject, but each noun is still singular on its own.

So the sentence means:

• one code lock
• and one padlock
• are new

If you meant several code locks and several padlocks, you would use plural nouns, for example:

• Kodelåsene og hengelåsene er nye.

The sentence follows a very common Norwegian pattern:

Subject + verb + complement

Here that gives:

• Kodelåsen og hengelåsen = subject
• er = verb
• nye = complement / predicate adjective

So the structure is:

Kodelåsen og hengelåsen | er | nye.

This is a normal declarative sentence.

Yes. Nye applies to the whole subject, so it describes both kodelåsen and hengelåsen.

In other words, the sentence says that both items are new.

If only one of them were new, you would need different wording, for example:

• Kodelåsen er ny, men hengelåsen er gammel.

In a yes/no question, Norwegian usually puts the verb first:

• Er kodelåsen og hengelåsen nye?

So the statement:

• Kodelåsen og hengelåsen er nye.

becomes the question:

• Er kodelåsen og hengelåsen nye?

Then Norwegian uses what learners often call double definiteness:

• den nye kodelåsen
• den nye hengelåsen

So:

• the new code lock and the new padlock
• den nye kodelåsen og den nye hengelåsen

This is different from the original sentence, where new comes after er:

• Kodelåsen og hengelåsen er nye.

When the adjective comes before a definite noun, Norwegian normally uses both:

• a definite article like den
• and the definite ending on the noun

So:

• kodelåsen = the code lock
• den nye kodelåsen = the new code lock