Just one guess, namely that the strokes are 7.5% of the height of the less than symbol.
\documentclass{article}
\usepackage{pict2e}
\makeatletter
\newcommand{\lgbar}{\mathrel{\mathpalette\dehaer@lgbar\relax}}
\newcommand{\dehaer@lgbar}[2]{%
\vcenter{\hbox{%
\sbox\z@{$\m@th#1<$}%
\setlength{\unitlength}{\dimexpr\ht\z@+\dp\z@}%
\linethickness{.075\unitlength}%
\begin{picture}(.225,1)
\roundcap
\polyline(0.1125,0)(0.1125,1)
\end{picture}%
}}%
}
\newcommand{\lgbbar}{\mathrel{\mathpalette\dehaer@lgbbar\relax}}
\newcommand{\dehaer@lgbbar}[2]{%
\vcenter{\hbox{%
\sbox\z@{$\m@th#1<$}%
\setlength{\unitlength}{\dimexpr\ht\z@+\dp\z@}%
\linethickness{.075\unitlength}%
\begin{picture}(.225,1)
\roundcap
\polyline(0.1125,0)(0.1125,0.4)
\polyline(0.1125,0.6)(0.1125,1)
\end{picture}%
}}%
}
\makeatother
\newcommand{\ltb}{<\lgbar}
\newcommand{\gtb}{\lgbar>}
\newcommand{\ltbb}{<\lgbbar}
\newcommand{\gtbb}{\lgbbar>}
\begin{document}
$a\gtbb b\ltbb c \gtb d\ltb e_{\ltb}$
\Large
$a\ltb b$
\end{document}