Where's the top of this pen?

这支笔的笔帽在哪儿？

《牛津词典》

She put down the pen on the top of the pad.

她放下笔，搁在本子上。

youdao

A color sensor on the top of the pen registers the color of the object you select, which in turn is displayed digitally on the back of the device for verification.

这支笔头是一个色彩传感器，用来采集你所选择目标的颜色，之后，它所采集出来的颜色将显示在笔杆的电子屏上，让使用者确认。

youdao

In other words, it's now just a matter of holding the pen directly above the top or bottom of the scrollable screen.

ENGADGET: Samsung Galaxy Note II review Mobile

The top of the pen, which always features the Montblanc star logo, is in the shape of the small bowler hat that was synonymous with the character.

FORBES: Writing Instruments As Objets D��Art

You will also be able to use the top button on the pen to select text and the button to erase.

ENGADGET: A closer look at the HTC Flyer's screen, stylus, and Scribe