Can I use variables for selectors?

I have this variable:

$gutter: 10;

I want to use it in a selector like so SCSS:

.grid+$gutter {
    background: red;
}

so the output becomes CSS:

.grid10 {
    background: red;
}

But this doesn't work. Is it possible?

$gutter: 10;

.grid#{$gutter} {
    background: red;
}

If used in a string for example in a url:

background: url('/ui/all/fonts/#{$filename}.woff')

From the Sass Reference on "Interpolation":

> You can also use SassScript variables in selectors and property names using #{} interpolation syntax:

$gutter: 10;

.grid#{$gutter} {
    background: red;
}

Furthermore, the @each directive is not needed to make interpolation work, and as your $gutter only contains one value, there's no need for a loop.

If you had multiple values to create rules for, you could then use a Sass list and @each:

$grid: 10, 40, 120, 240;

@each $i in $grid {
  .g#{$i}{
    width: #{$i}px;
  }
}

...to generate the following output:

.g10  { width: 10px; }
.g40  { width: 40px; }
.g120 { width: 120px; }
.g240 { width: 240px; }

Here are some more examples..

Here is the solution

$gutter: 10;

@each $i in $gutter {
  .g#{$i}{
     background: red;
  }
}

if it would be a vendor prefix, in my case the mixin did not compile. So I used this example

@mixin range-thumb()
  -webkit-appearance: none;
  border: 1px solid #000000;
  height: 36px;
  width: 16px;
  border-radius: 3px;
  background: #ffffff;
  cursor: pointer;
  margin-top: -14px; 
  box-shadow: 1px 1px 1px #000000, 0px 0px 1px #0d0d0d;

input[type=range]
  &::-webkit-slider-thumb
    @include range-thumb()
  &::-moz-range-thumb
    @include range-thumb()
  &::-ms-thumb
    @include range-thumb()