مفتاح الربط وميزان التسوية في صندوق الأدوات.

Arabic often leaves out the verb to be in the present tense.

So مفتاح الربط وميزان التسوية في صندوق الأدوات literally looks like:

• the wrench and the level
• in the toolbox

But it means The wrench and the level are in the toolbox.

This is a very common Arabic pattern:

• الكتاب على الطاولة = The book is on the table
• no separate word for is is needed in the present tense

If you wanted a past tense, then Arabic would use a verb:

• كان مفتاح الربط في صندوق الأدوات = The wrench was in the toolbox

By itself, مفتاح usually means key.

But Arabic also uses مفتاح for certain tools that turn or tighten something, so in tool vocabulary it can mean something like wrench or spanner, depending on context.

The phrase مفتاح الربط is literally something like:

• مفتاح = key / turning tool
• الربط = fastening / tightening / joining

So the whole expression means the tightening tool, i.e. the wrench.

This is normal technical vocabulary in Arabic: a word may have a broader literal meaning, but in context it becomes the standard name of a tool.

Yes. Both are examples of the iḍāfa structure, often called a genitive construction in English grammar discussions.

ميزان التسوية

Literally:

• ميزان = measure / balance / level
• التسوية = leveling / making even

Together: leveling instrument → level or spirit level

مفتاح الربط

Literally:

• مفتاح = key / wrench
• الربط = fastening / tightening

Together: fastening tool → wrench

So both tool names are made from:

• a main noun
• followed by another noun that specifies its function

Because in an iḍāfa construction, the first noun does not take ال.

That is a basic rule.

So Arabic says:

• مفتاح الربط not
• المفتاح الربط

The definiteness of the whole phrase comes from the second noun:

• الربط is definite because it has الـ
• therefore مفتاح الربط as a whole is definite

The same thing happens in:

• صندوق الأدوات = the toolbox
• not الصندوق الأدوات

So in iḍāfa:

• first noun: no الـ
• second noun: may be definite or indefinite
• the second noun controls whether the whole phrase is definite

Because the first word in an iḍāfa construction does not take tanwīn.

For example:

• مفتاحٌ = a key
• but مفتاحُ الربطِ = the wrench / a wrench of fastening

And:

• صندوقٌ = a box
• but صندوقُ الأدواتِ = the toolbox / box of tools

So when a noun becomes the first part of iḍāfa:

• it loses tanwīn
• it also cannot take الـ

That is why مفتاح and صندوق appear in this bare form.

Again, this is because صندوق الأدوات is an iḍāfa.

It literally means:

• box of the tools

In natural English, that becomes the toolbox or the tools box, though toolbox is the normal translation.

Here is the structure:

• صندوق = box
• الأدوات = the tools

Since الأدوات is definite, the whole phrase becomes definite:

• صندوق الأدوات = the toolbox

The first noun صندوق cannot take الـ because it is the first part of iḍāfa.

A fully vocalized version would be:

مِفْتاحُ الرَّبْطِ وَمِيزانُ التَّسْوِيَةِ في صُنْدوقِ الأَدَواتِ

Here is why:

• مفتاحُ — nominative, because it is part of the subject
• الربطِ — genitive, because it is the second noun in iḍāfa
• ميزانُ — nominative, also part of the subject
• التسويةِ — genitive, as second noun in iḍāfa
• في — preposition
• صندوقِ — genitive after في
• الأدواتِ — genitive as the second noun in iḍāfa

In normal everyday writing, these short vowel endings are usually not written.

في means in.

It introduces a prepositional phrase:

• في صندوق الأدوات = in the toolbox

It also makes the following noun genitive:

• صندوقِ

So this part of the sentence tells you the location of the tools.

This is very common in Arabic:

• في البيت = in the house
• في السيارة = in the car
• في الحقيبة = in the bag

Yes. و is the normal Arabic word for and.

So the sentence names two separate items:

• مفتاح الربط = the wrench
• ميزان التسوية = the level

Then it says both of them are in the toolbox.

So the structure is:

• item 1
• و
• item 2
• location phrase

In other words, it does not mean one combined object. It means two different tools.

A helpful pronunciation is:

miftāḥ ar-rabṭ wa-mīzān at-taswiyah fī ṣundūq al-adawāt

A few points:

• الربط is pronounced ar-rabṭ, not al-rabṭ, because ر is a sun letter, so the l sound assimilates
• التسوية is pronounced at-taswiyah, because ت is also a sun letter
• الأدوات is pronounced al-adawāt, because here the l does not assimilate

So:

• الرَّبط → ar-rabṭ
• التَّسوية → at-taswiyah
• الأدوات → al-adawāt

Yes, but the style would be a little different.

Your sentence is a very natural nominal sentence:

• مفتاح الربط وميزان التسوية في صندوق الأدوات
• The wrench and the level are in the toolbox

You could also say something like:

• هناك مفتاح ربط وميزان تسوية في صندوق الأدوات
• There is a wrench and a level in the toolbox

Or:

• يوجد مفتاح ربط وميزان تسوية في صندوق الأدوات
• There is a wrench and a level in the toolbox

The difference is mainly about structure and emphasis:

• nominal sentence: more like The wrench and the level are in the toolbox
• هناك / يوجد: more like There is / there are... in the toolbox

So your original sentence is perfectly normal and elegant.

In this exact form, the noun phrases are definite because they are iḍāfa constructions whose second nouns are definite:

• مفتاح الربط = definite
• ميزان التسوية = definite
• صندوق الأدوات = definite

So the most direct reading is:

• the wrench and the level are in the toolbox

If Arabic wanted a more clearly indefinite meaning, it would usually change the wording, for example by using less definite-looking expressions or a different context.

That said, translation into English can still depend on context, especially in technical manuals or labels. But grammatically, this Arabic sentence is built as a definite sentence.

Here are the core meanings:

• مفتاح = key; also wrench/spanner in tool vocabulary
• ربط = tying, fastening, tightening, connecting
• ميزان = scale, balance, measure, level
• تسوية = leveling, making even, smoothing
• في = in
• صندوق = box
• أدوات = tools

So the sentence is a good example of how Arabic often builds technical meanings from basic root meanings.

For a learner, it helps to see both levels:

• the literal pieces
• the natural tool name in context