public function color_overlay_transparency( WP_Customize_Manager $wp_customize ) {

		$wp_customize->add_setting(
			'hero_image_color_overlay',
			array(
				'default'           => $this->get_color_overlay_transparency_default_value(),
				'sanitize_callback' => 'absint',
				'transport'         => 'postMessage',
			)
		);

		$wp_customize->add_control(
			'hero_image_color_overlay',
			array(
				'label'           => esc_html__( 'Hero Background Overlay', 'rock' ),
				'description'     => esc_html__( 'Control the color overlay transparency when using a custom Header Image.', 'rock' ),
				'section'         => 'colors-header',
				'priority'        => 20,
				'active_callback' => 'rock_has_hero_image',
				'type'            => 'range',
				'input_attrs'     => array(
					'min'  => 0,
					'max'  => 100,
					'step' => 1,
				),
			)
		);

	}