Or, you can make things simple and pick up some pre-made crutches or filters for rolling
@ Values from Table 3
AsiaPacific consensus for the management of osteoporosis in men Chun-Feng Huang, Cheng-Jung Ho, Sung-Yen Lin, Jawl-Shan Hwang, Ta-Wei Tai, Jung-Fu Chen, Shih-Te Tu, Ding-Cheng Chan, Rong-Sen Yang, Hsuan-Yu Chen, Keh-Sung Tsai, Tien-Tsai Cheng, Fang-Ping Chen, Wei-Chieh Hung, Yin-Fan Chang, Der-Sheng Han, Manju Chandran, Ang Seng Bin, Joon Kiong Lee, Swan Sim Yeap, Yoon-Sok Chung, Kwang-Kyoun Kim, Peter Ebeling, Unnop Jaisamrarn, Dipendra Pandey, Serge Ferrari, Eugene McCloskey, Natthinee Charatcharoenwitthaya, Akira Taguchi, Sarath Lekamwasam, Tuan Van Nguyen, E
Looks to me like a gas lighter or similar has been held to it