Blending Options>Gradient Overlay
Gradient’s parameters: 

Selecting the same instrument, it’s possible to represent one of the strengthening elements, having the color
383839.

The layer’s parameters:
Fill 30% on the layers.
Blending Options>Outer Glow

Make a copy of the new made layer and choose the
Free Transform option to make it smaller. Place it the way it is demonstrated below and change its parameters also: