private function query_customers( $args = array() ) {

		// default users per page
		$users_per_page = get_option( 'posts_per_page' );

		// Set base query arguments
		$query_args = array(
			'fields'  => 'ID',
			'role'    => 'customer',
			'orderby' => 'registered',
			'number'  => $users_per_page,
		);

		// Custom Role
		if ( ! empty( $args['role'] ) ) {
			$query_args['role'] = $args['role'];
		}

		// Search
		if ( ! empty( $args['q'] ) ) {
			$query_args['search'] = $args['q'];
		}

		// Limit number of users returned
		if ( ! empty( $args['limit'] ) ) {
			if ( -1 == $args['limit'] ) {
				unset( $query_args['number'] );
			} else {
				$query_args['number'] = absint( $args['limit'] );
				$users_per_page       = absint( $args['limit'] );
			}
		} else {
			$args['limit'] = $query_args['number'];
		}

		// Page
		$page = ( isset( $args['page'] ) ) ? absint( $args['page'] ) : 1;

		// Offset
		if ( ! empty( $args['offset'] ) ) {
			$query_args['offset'] = absint( $args['offset'] );
		} else {
			$query_args['offset'] = $users_per_page * ( $page - 1 );
		}

		// Created date
		if ( ! empty( $args['created_at_min'] ) ) {
			$this->created_at_min = $this->server->parse_datetime( $args['created_at_min'] );
		}

		if ( ! empty( $args['created_at_max'] ) ) {
			$this->created_at_max = $this->server->parse_datetime( $args['created_at_max'] );
		}

		// Order (ASC or DESC, ASC by default)
		if ( ! empty( $args['order'] ) ) {
			$query_args['order'] = $args['order'];
		}

		// Order by
		if ( ! empty( $args['orderby'] ) ) {
			$query_args['orderby'] = $args['orderby'];

			// Allow sorting by meta value
			if ( ! empty( $args['orderby_meta_key'] ) ) {
				$query_args['meta_key'] = $args['orderby_meta_key'];
			}
		}

		$query = new WP_User_Query( $query_args );

		// Helper members for pagination headers
		$query->total_pages = ( -1 == $args['limit'] ) ? 1 : ceil( $query->get_total() / $users_per_page );
		$query->page = $page;

		return $query;
	}